{"api_version":"1","generated_at":"2026-06-03T09:09:10+00:00","cve":"CVE-2026-22977","urls":{"html":"https://cve.report/CVE-2026-22977","api":"https://cve.report/api/cve/CVE-2026-22977.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-22977","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-22977"},"summary":{"title":"net: sock: fix hardened usercopy panic in sock_recv_errqueue","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sock: fix hardened usercopy panic in sock_recv_errqueue\n\nskbuff_fclone_cache was created without defining a usercopy region,\n[1] unlike skbuff_head_cache which properly whitelists the cb[] field.\n[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is\nenabled and the kernel attempts to copy sk_buff.cb data to userspace\nvia sock_recv_errqueue() -> put_cmsg().\n\nThe crash occurs when: 1. TCP allocates an skb using alloc_skb_fclone()\n   (from skbuff_fclone_cache) [1]\n2. The skb is cloned via skb_clone() using the pre-allocated fclone\n[3] 3. The cloned skb is queued to sk_error_queue for timestamp\nreporting 4. Userspace reads the error queue via recvmsg(MSG_ERRQUEUE)\n5. sock_recv_errqueue() calls put_cmsg() to copy serr->ee from skb->cb\n[4] 6. __check_heap_object() fails because skbuff_fclone_cache has no\n   usercopy whitelist [5]\n\nWhen cloned skbs allocated from skbuff_fclone_cache are used in the\nsocket error queue, accessing the sock_exterr_skb structure in skb->cb\nvia put_cmsg() triggers a usercopy hardening violation:\n\n[    5.379589] usercopy: Kernel memory exposure attempt detected from SLUB object 'skbuff_fclone_cache' (offset 296, size 16)!\n[    5.382796] kernel BUG at mm/usercopy.c:102!\n[    5.383923] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n[    5.384903] CPU: 1 UID: 0 PID: 138 Comm: poc_put_cmsg Not tainted 6.12.57 #7\n[    5.384903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[    5.384903] RIP: 0010:usercopy_abort+0x6c/0x80\n[    5.384903] Code: 1a 86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48 c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff <0f> 0b 490\n[    5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246\n[    5.384903] RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74\n[    5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff87b973a0\n[    5.384903] RBP: 0000000000000010 R08: 0000000000000000 R09: fffffbfff0f72e74\n[    5.384903] R10: 0000000000000003 R11: 79706f6372657375 R12: 0000000000000001\n[    5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15: ffffea00003c2b00\n[    5.384903] FS:  0000000011bc4380(0000) GS:ffff8880bf100000(0000) knlGS:0000000000000000\n[    5.384903] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[    5.384903] CR2: 000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0\n[    5.384903] PKRU: 55555554\n[    5.384903] Call Trace:\n[    5.384903]  <TASK>\n[    5.384903]  __check_heap_object+0x9a/0xd0\n[    5.384903]  __check_object_size+0x46c/0x690\n[    5.384903]  put_cmsg+0x129/0x5e0\n[    5.384903]  sock_recv_errqueue+0x22f/0x380\n[    5.384903]  tls_sw_recvmsg+0x7ed/0x1960\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? schedule+0x6d/0x270\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? mutex_unlock+0x81/0xd0\n[    5.384903]  ? __pfx_mutex_unlock+0x10/0x10\n[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10\n[    5.384903]  ? _raw_spin_lock_irqsave+0x8f/0xf0\n[    5.384903]  ? _raw_read_unlock_irqrestore+0x20/0x40\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n\nThe crash offset 296 corresponds to skb2->cb within skbuff_fclones:\n  - sizeof(struct sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -\n  offset of skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =\n  272 + 24 (inside sock_exterr_skb.ee)\n\nThis patch uses a local stack variable as a bounce buffer to avoid the hardened usercopy check failure.\n\n[1] https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885\n[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5104\n[3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5566\n[4] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5491\n[5] https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719","state":"PUBLISHED","assigner":"Linux","published_at":"2026-01-21 14:16:06","updated_at":"2026-06-02 14:16:46"},"problem_types":["CWE-476"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/582a5e922a9652fcbb7d0165c95d5b20aa37575d","name":"https://git.kernel.org/stable/c/582a5e922a9652fcbb7d0165c95d5b20aa37575d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/005671c60fcf1dbdb8bddf12a62568fd5e4ec391","name":"https://git.kernel.org/stable/c/005671c60fcf1dbdb8bddf12a62568fd5e4ec391","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2a71a1a8d0ed718b1c7a9ac61f07e5755c47ae20","name":"https://git.kernel.org/stable/c/2a71a1a8d0ed718b1c7a9ac61f07e5755c47ae20","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-253495.html","name":"https://cert-portal.siemens.com/productcert/html/ssa-253495.html","refsource":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/88dd6be7ebb3153b662c2cebcb06e032a92857f5","name":"https://git.kernel.org/stable/c/88dd6be7ebb3153b662c2cebcb06e032a92857f5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8c6901aa29626e35045130bac09b75f791acca85","name":"https://git.kernel.org/stable/c/8c6901aa29626e35045130bac09b75f791acca85","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e00b169eaac5f7cdbf710c354c8fa76d02009115","name":"https://git.kernel.org/stable/c/e00b169eaac5f7cdbf710c354c8fa76d02009115","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c655d2167bf014d4c61b4faeca59b60ff9b9f6b1","name":"https://git.kernel.org/stable/c/c655d2167bf014d4c61b4faeca59b60ff9b9f6b1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-22977","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-22977","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 88dd6be7ebb3153b662c2cebcb06e032a92857f5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 c655d2167bf014d4c61b4faeca59b60ff9b9f6b1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 8c6901aa29626e35045130bac09b75f791acca85 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 582a5e922a9652fcbb7d0165c95d5b20aa37575d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 005671c60fcf1dbdb8bddf12a62568fd5e4ec391 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 e00b169eaac5f7cdbf710c354c8fa76d02009115 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6d07d1cd300f4c7e16005f881fea388164999cc8 2a71a1a8d0ed718b1c7a9ac61f07e5755c47ae20 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.248 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.198 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.161 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.121 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.66 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.6 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19 * original_commit_for_fix","platforms":[]},{"source":"ADP","vendor":"Siemens","product":"RUGGEDCOM RST2428P","version":"affected V4.0 custom","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2026","cve_id":"22977","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"affected":[{"defaultStatus":"unknown","product":"RUGGEDCOM RST2428P","vendor":"Siemens","versions":[{"lessThan":"V4.0","status":"affected","version":"0","versionType":"custom"}]}],"providerMetadata":{"dateUpdated":"2026-06-02T13:00:47.626Z","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","shortName":"siemens-SADP"},"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-253495.html"}],"x_adpType":"supplier"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/core/sock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"88dd6be7ebb3153b662c2cebcb06e032a92857f5","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"c655d2167bf014d4c61b4faeca59b60ff9b9f6b1","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"8c6901aa29626e35045130bac09b75f791acca85","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"582a5e922a9652fcbb7d0165c95d5b20aa37575d","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"005671c60fcf1dbdb8bddf12a62568fd5e4ec391","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"e00b169eaac5f7cdbf710c354c8fa76d02009115","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"},{"lessThan":"2a71a1a8d0ed718b1c7a9ac61f07e5755c47ae20","status":"affected","version":"6d07d1cd300f4c7e16005f881fea388164999cc8","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/core/sock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.16"},{"lessThan":"4.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.248","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.198","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.161","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.121","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.66","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.19","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.248","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.198","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.161","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.121","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.66","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.6","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19","versionStartIncluding":"4.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sock: fix hardened usercopy panic in sock_recv_errqueue\n\nskbuff_fclone_cache was created without defining a usercopy region,\n[1] unlike skbuff_head_cache which properly whitelists the cb[] field.\n[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is\nenabled and the kernel attempts to copy sk_buff.cb data to userspace\nvia sock_recv_errqueue() -> put_cmsg().\n\nThe crash occurs when: 1. TCP allocates an skb using alloc_skb_fclone()\n   (from skbuff_fclone_cache) [1]\n2. The skb is cloned via skb_clone() using the pre-allocated fclone\n[3] 3. The cloned skb is queued to sk_error_queue for timestamp\nreporting 4. Userspace reads the error queue via recvmsg(MSG_ERRQUEUE)\n5. sock_recv_errqueue() calls put_cmsg() to copy serr->ee from skb->cb\n[4] 6. __check_heap_object() fails because skbuff_fclone_cache has no\n   usercopy whitelist [5]\n\nWhen cloned skbs allocated from skbuff_fclone_cache are used in the\nsocket error queue, accessing the sock_exterr_skb structure in skb->cb\nvia put_cmsg() triggers a usercopy hardening violation:\n\n[    5.379589] usercopy: Kernel memory exposure attempt detected from SLUB object 'skbuff_fclone_cache' (offset 296, size 16)!\n[    5.382796] kernel BUG at mm/usercopy.c:102!\n[    5.383923] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n[    5.384903] CPU: 1 UID: 0 PID: 138 Comm: poc_put_cmsg Not tainted 6.12.57 #7\n[    5.384903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[    5.384903] RIP: 0010:usercopy_abort+0x6c/0x80\n[    5.384903] Code: 1a 86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48 c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff <0f> 0b 490\n[    5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246\n[    5.384903] RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74\n[    5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff87b973a0\n[    5.384903] RBP: 0000000000000010 R08: 0000000000000000 R09: fffffbfff0f72e74\n[    5.384903] R10: 0000000000000003 R11: 79706f6372657375 R12: 0000000000000001\n[    5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15: ffffea00003c2b00\n[    5.384903] FS:  0000000011bc4380(0000) GS:ffff8880bf100000(0000) knlGS:0000000000000000\n[    5.384903] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[    5.384903] CR2: 000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0\n[    5.384903] PKRU: 55555554\n[    5.384903] Call Trace:\n[    5.384903]  <TASK>\n[    5.384903]  __check_heap_object+0x9a/0xd0\n[    5.384903]  __check_object_size+0x46c/0x690\n[    5.384903]  put_cmsg+0x129/0x5e0\n[    5.384903]  sock_recv_errqueue+0x22f/0x380\n[    5.384903]  tls_sw_recvmsg+0x7ed/0x1960\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? schedule+0x6d/0x270\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? mutex_unlock+0x81/0xd0\n[    5.384903]  ? __pfx_mutex_unlock+0x10/0x10\n[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10\n[    5.384903]  ? _raw_spin_lock_irqsave+0x8f/0xf0\n[    5.384903]  ? _raw_read_unlock_irqrestore+0x20/0x40\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n\nThe crash offset 296 corresponds to skb2->cb within skbuff_fclones:\n  - sizeof(struct sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -\n  offset of skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =\n  272 + 24 (inside sock_exterr_skb.ee)\n\nThis patch uses a local stack variable as a bounce buffer to avoid the hardened usercopy check failure.\n\n[1] https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885\n[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5104\n[3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5566\n[4] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5491\n[5] https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719"}],"providerMetadata":{"dateUpdated":"2026-05-11T21:57:36.693Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/88dd6be7ebb3153b662c2cebcb06e032a92857f5"},{"url":"https://git.kernel.org/stable/c/c655d2167bf014d4c61b4faeca59b60ff9b9f6b1"},{"url":"https://git.kernel.org/stable/c/8c6901aa29626e35045130bac09b75f791acca85"},{"url":"https://git.kernel.org/stable/c/582a5e922a9652fcbb7d0165c95d5b20aa37575d"},{"url":"https://git.kernel.org/stable/c/005671c60fcf1dbdb8bddf12a62568fd5e4ec391"},{"url":"https://git.kernel.org/stable/c/e00b169eaac5f7cdbf710c354c8fa76d02009115"},{"url":"https://git.kernel.org/stable/c/2a71a1a8d0ed718b1c7a9ac61f07e5755c47ae20"}],"title":"net: sock: fix hardened usercopy panic in sock_recv_errqueue","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-22977","datePublished":"2026-01-21T13:08:54.858Z","dateReserved":"2026-01-13T15:37:45.935Z","dateUpdated":"2026-06-02T13:00:47.626Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-01-21 14:16:06","lastModifiedDate":"2026-06-02 14:16:46","problem_types":["CWE-476"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"5.10.248","matchCriteriaId":"28823BF6-2E21-40F0-9BF2-FB2E3202B725"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.198","matchCriteriaId":"82159CAA-B6BA-43C6-85D8-65BDBC175A7E"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.161","matchCriteriaId":"E135B7E2-61FC-4DC1-8570-ABD67894FFDE"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.121","matchCriteriaId":"BB7A164B-7422-4A1C-82FB-5FCAEE53C06C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.66","matchCriteriaId":"F72B884C-B44F-40E4-9895-CE421AC663D0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.6","matchCriteriaId":"879529BC-5B4C-4EBE-BF1D-1A31404A8B2E"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*","matchCriteriaId":"17B67AA7-40D6-4AFA-8459-F200F3D7CFD1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*","matchCriteriaId":"C47E4CC9-C826-4FA9-B014-7FE3D9B318B2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*","matchCriteriaId":"F71D92C0-C023-48BD-B3B6-70B638EEE298"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*","matchCriteriaId":"13580667-0A98-40CC-B29F-D12790B91BDB"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"22977","Ordinal":"1","Title":"net: sock: fix hardened usercopy panic in sock_recv_errqueue","CVE":"CVE-2026-22977","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"22977","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sock: fix hardened usercopy panic in sock_recv_errqueue\n\nskbuff_fclone_cache was created without defining a usercopy region,\n[1] unlike skbuff_head_cache which properly whitelists the cb[] field.\n[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is\nenabled and the kernel attempts to copy sk_buff.cb data to userspace\nvia sock_recv_errqueue() -> put_cmsg().\n\nThe crash occurs when: 1. TCP allocates an skb using alloc_skb_fclone()\n   (from skbuff_fclone_cache) [1]\n2. The skb is cloned via skb_clone() using the pre-allocated fclone\n[3] 3. The cloned skb is queued to sk_error_queue for timestamp\nreporting 4. Userspace reads the error queue via recvmsg(MSG_ERRQUEUE)\n5. sock_recv_errqueue() calls put_cmsg() to copy serr->ee from skb->cb\n[4] 6. __check_heap_object() fails because skbuff_fclone_cache has no\n   usercopy whitelist [5]\n\nWhen cloned skbs allocated from skbuff_fclone_cache are used in the\nsocket error queue, accessing the sock_exterr_skb structure in skb->cb\nvia put_cmsg() triggers a usercopy hardening violation:\n\n[    5.379589] usercopy: Kernel memory exposure attempt detected from SLUB object 'skbuff_fclone_cache' (offset 296, size 16)!\n[    5.382796] kernel BUG at mm/usercopy.c:102!\n[    5.383923] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n[    5.384903] CPU: 1 UID: 0 PID: 138 Comm: poc_put_cmsg Not tainted 6.12.57 #7\n[    5.384903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[    5.384903] RIP: 0010:usercopy_abort+0x6c/0x80\n[    5.384903] Code: 1a 86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48 c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff <0f> 0b 490\n[    5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246\n[    5.384903] RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74\n[    5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff87b973a0\n[    5.384903] RBP: 0000000000000010 R08: 0000000000000000 R09: fffffbfff0f72e74\n[    5.384903] R10: 0000000000000003 R11: 79706f6372657375 R12: 0000000000000001\n[    5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15: ffffea00003c2b00\n[    5.384903] FS:  0000000011bc4380(0000) GS:ffff8880bf100000(0000) knlGS:0000000000000000\n[    5.384903] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[    5.384903] CR2: 000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0\n[    5.384903] PKRU: 55555554\n[    5.384903] Call Trace:\n[    5.384903]  <TASK>\n[    5.384903]  __check_heap_object+0x9a/0xd0\n[    5.384903]  __check_object_size+0x46c/0x690\n[    5.384903]  put_cmsg+0x129/0x5e0\n[    5.384903]  sock_recv_errqueue+0x22f/0x380\n[    5.384903]  tls_sw_recvmsg+0x7ed/0x1960\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? schedule+0x6d/0x270\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? mutex_unlock+0x81/0xd0\n[    5.384903]  ? __pfx_mutex_unlock+0x10/0x10\n[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10\n[    5.384903]  ? _raw_spin_lock_irqsave+0x8f/0xf0\n[    5.384903]  ? _raw_read_unlock_irqrestore+0x20/0x40\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n\nThe crash offset 296 corresponds to skb2->cb within skbuff_fclones:\n  - sizeof(struct sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -\n  offset of skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =\n  272 + 24 (inside sock_exterr_skb.ee)\n\nThis patch uses a local stack variable as a bounce buffer to avoid the hardened usercopy check failure.\n\n[1] https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885\n[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5104\n[3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5566\n[4] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5491\n[5] https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719","Type":"Description","Title":"net: sock: fix hardened usercopy panic in sock_recv_errqueue"}]}}}