{"api_version":"1","generated_at":"2026-10-23T18:44:12+00:00","cve":"CVE-2026-99033","urls":{"html":"https://cve.report/CVE-2026-99033","api":"https://cve.report/api/cve/CVE-2026-99033.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-99033","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-99033"},"summary":{"title":"net/packet: guard the ll header push in packet_rcv_spkt()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: guard the ll header push in packet_rcv_spkt()\n\npacket_rcv_spkt() restores the link layer header with\n\n\tskb_push(skb, skb->data - skb_mac_header(skb));\n\nThat subtraction is only meaningful when the device actually has a link\nlayer header.  packet_rcv() and tpacket_rcv() both wrap it in\ndev_has_header(), which is also the predicate the block comment at the\ntop of the file states the restore in terms of; packet_rcv_spkt() does\nnot.  commit d549699048b4 (\"net/packet: fix packet receive on L3\ndevices without visible hard header\") introduced the helper and changed\nthe two call sites, and this one stayed behind.\n\nA device without a visible ll header can leave skb->mac_header at the\n0xFFFF sentinel that __alloc_skb() initialises it to.  A CAN skb does:\ninit_can_skb() sets pkt_type and ip_summed but does not reset the\nheaders, and commit 9f10374bb024 (\"can: remove private CAN skb\nheadroom infrastructure\") dropped the skb_reset_*_header() calls that\nused to be there.  skb_mac_header() is then 0xFFFF, the length becomes\na large negative number and skb_push() reports it through\nskb_under_panic() -- from softirq context, so it is a full system panic\neven with panic_on_oops=0:\n\n  skbuff: skb_under_panic: text:ffffffff8bd21bc1 len:-65455 put:-65471 head:... data:... tail:0x50 end:0x180 dev:can0\n  kernel BUG at net/core/skbuff.c:214!\n  RIP: 0010:skb_panic+0x50/0x60\n  Call Trace:\n   <IRQ>\n   skb_push+0x38/0x40\n   packet_rcv_spkt+0xe1/0x170\n   __netif_receive_skb_core.constprop.0+0x7e8/0xd30\n   ...\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe socket type is reachable: packet_create() accepts SOCK_PACKET\nalongside SOCK_RAW and SOCK_DGRAM behind the same CAP_NET_RAW check,\nand neither the socket length nor a capability check keeps it away\nfrom a CAN interface.\n\nThe missing skb_reset_*_header() calls in init_can_skb() are a\nregression in their own right and are being fixed separately, but a\npacket socket should not turn a link layer that did not initialise its\nmac header into a kernel panic.  Guard the push the way the other two\nreceive paths do.\n\nTested on v7.3-rc5 under QEMU with a slcan device on a pty, which is\nthe driver RX path: vcan does not reproduce it, because can_send()\nresets the headers on the way out.  One SOCK_PACKET socket bound to\ncan0 and one frame written into the line discipline panics an\nunpatched kernel with the trace above; the same image with this patch\nprints no panic and powers off normally.  Both kernels are this tree,\ndefconfig plus CONFIG_CAN_SLCAN=y, differing only in this hunk.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-23 13:17:26","updated_at":"2026-10-23 13:17:26"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/28bc1ef699610ee09ce3d46a00552f5a0a0144bd","name":"https://git.kernel.org/stable/c/28bc1ef699610ee09ce3d46a00552f5a0a0144bd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/00fbf71e74115f7628fc0880b855434b1e70c40c","name":"https://git.kernel.org/stable/c/00fbf71e74115f7628fc0880b855434b1e70c40c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3efe0e0944157fdd2072b4dc7eb0491a317ed272","name":"https://git.kernel.org/stable/c/3efe0e0944157fdd2072b4dc7eb0491a317ed272","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d8a24b9e1774a93943caf68d48c5e17be432220b","name":"https://git.kernel.org/stable/c/d8a24b9e1774a93943caf68d48c5e17be432220b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be","name":"https://git.kernel.org/stable/c/31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-99033","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99033","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d549699048b4b5c22dd710455bcdb76966e55aa3 d8a24b9e1774a93943caf68d48c5e17be432220b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d549699048b4b5c22dd710455bcdb76966e55aa3 31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d549699048b4b5c22dd710455bcdb76966e55aa3 3efe0e0944157fdd2072b4dc7eb0491a317ed272 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d549699048b4b5c22dd710455bcdb76966e55aa3 00fbf71e74115f7628fc0880b855434b1e70c40c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d549699048b4b5c22dd710455bcdb76966e55aa3 28bc1ef699610ee09ce3d46a00552f5a0a0144bd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dadddde259a19105ee69e788835f4d4552767aa9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.9.13 5.10 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.10","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.160 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.113 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.57 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.11 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/packet/af_packet.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"d8a24b9e1774a93943caf68d48c5e17be432220b","status":"affected","version":"d549699048b4b5c22dd710455bcdb76966e55aa3","versionType":"git"},{"lessThan":"31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be","status":"affected","version":"d549699048b4b5c22dd710455bcdb76966e55aa3","versionType":"git"},{"lessThan":"3efe0e0944157fdd2072b4dc7eb0491a317ed272","status":"affected","version":"d549699048b4b5c22dd710455bcdb76966e55aa3","versionType":"git"},{"lessThan":"00fbf71e74115f7628fc0880b855434b1e70c40c","status":"affected","version":"d549699048b4b5c22dd710455bcdb76966e55aa3","versionType":"git"},{"lessThan":"28bc1ef699610ee09ce3d46a00552f5a0a0144bd","status":"affected","version":"d549699048b4b5c22dd710455bcdb76966e55aa3","versionType":"git"},{"status":"affected","version":"dadddde259a19105ee69e788835f4d4552767aa9","versionType":"git"},{"lessThan":"5.10","status":"affected","version":"5.9.13","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/packet/af_packet.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.10"},{"lessThan":"5.10","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.160","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.113","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.57","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.160","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.113","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.57","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.11","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"5.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.9.13","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: guard the ll header push in packet_rcv_spkt()\n\npacket_rcv_spkt() restores the link layer header with\n\n\tskb_push(skb, skb->data - skb_mac_header(skb));\n\nThat subtraction is only meaningful when the device actually has a link\nlayer header.  packet_rcv() and tpacket_rcv() both wrap it in\ndev_has_header(), which is also the predicate the block comment at the\ntop of the file states the restore in terms of; packet_rcv_spkt() does\nnot.  commit d549699048b4 (\"net/packet: fix packet receive on L3\ndevices without visible hard header\") introduced the helper and changed\nthe two call sites, and this one stayed behind.\n\nA device without a visible ll header can leave skb->mac_header at the\n0xFFFF sentinel that __alloc_skb() initialises it to.  A CAN skb does:\ninit_can_skb() sets pkt_type and ip_summed but does not reset the\nheaders, and commit 9f10374bb024 (\"can: remove private CAN skb\nheadroom infrastructure\") dropped the skb_reset_*_header() calls that\nused to be there.  skb_mac_header() is then 0xFFFF, the length becomes\na large negative number and skb_push() reports it through\nskb_under_panic() -- from softirq context, so it is a full system panic\neven with panic_on_oops=0:\n\n  skbuff: skb_under_panic: text:ffffffff8bd21bc1 len:-65455 put:-65471 head:... data:... tail:0x50 end:0x180 dev:can0\n  kernel BUG at net/core/skbuff.c:214!\n  RIP: 0010:skb_panic+0x50/0x60\n  Call Trace:\n   <IRQ>\n   skb_push+0x38/0x40\n   packet_rcv_spkt+0xe1/0x170\n   __netif_receive_skb_core.constprop.0+0x7e8/0xd30\n   ...\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe socket type is reachable: packet_create() accepts SOCK_PACKET\nalongside SOCK_RAW and SOCK_DGRAM behind the same CAP_NET_RAW check,\nand neither the socket length nor a capability check keeps it away\nfrom a CAN interface.\n\nThe missing skb_reset_*_header() calls in init_can_skb() are a\nregression in their own right and are being fixed separately, but a\npacket socket should not turn a link layer that did not initialise its\nmac header into a kernel panic.  Guard the push the way the other two\nreceive paths do.\n\nTested on v7.3-rc5 under QEMU with a slcan device on a pty, which is\nthe driver RX path: vcan does not reproduce it, because can_send()\nresets the headers on the way out.  One SOCK_PACKET socket bound to\ncan0 and one frame written into the line discipline panics an\nunpatched kernel with the trace above; the same image with this patch\nprints no panic and powers off normally.  Both kernels are this tree,\ndefconfig plus CONFIG_CAN_SLCAN=y, differing only in this hunk."}],"providerMetadata":{"dateUpdated":"2026-10-23T12:21:37.662Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/d8a24b9e1774a93943caf68d48c5e17be432220b"},{"url":"https://git.kernel.org/stable/c/31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be"},{"url":"https://git.kernel.org/stable/c/3efe0e0944157fdd2072b4dc7eb0491a317ed272"},{"url":"https://git.kernel.org/stable/c/00fbf71e74115f7628fc0880b855434b1e70c40c"},{"url":"https://git.kernel.org/stable/c/28bc1ef699610ee09ce3d46a00552f5a0a0144bd"}],"title":"net/packet: guard the ll header push in packet_rcv_spkt()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-99033","datePublished":"2026-10-23T12:21:37.662Z","dateReserved":"2026-09-25T10:25:14.387Z","dateUpdated":"2026-10-23T12:21:37.662Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-23 13:17:26","lastModifiedDate":"2026-10-23 13:17:26","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"99033","Ordinal":"1","Title":"net/packet: guard the ll header push in packet_rcv_spkt()","CVE":"CVE-2026-99033","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"99033","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: guard the ll header push in packet_rcv_spkt()\n\npacket_rcv_spkt() restores the link layer header with\n\n\tskb_push(skb, skb->data - skb_mac_header(skb));\n\nThat subtraction is only meaningful when the device actually has a link\nlayer header.  packet_rcv() and tpacket_rcv() both wrap it in\ndev_has_header(), which is also the predicate the block comment at the\ntop of the file states the restore in terms of; packet_rcv_spkt() does\nnot.  commit d549699048b4 (\"net/packet: fix packet receive on L3\ndevices without visible hard header\") introduced the helper and changed\nthe two call sites, and this one stayed behind.\n\nA device without a visible ll header can leave skb->mac_header at the\n0xFFFF sentinel that __alloc_skb() initialises it to.  A CAN skb does:\ninit_can_skb() sets pkt_type and ip_summed but does not reset the\nheaders, and commit 9f10374bb024 (\"can: remove private CAN skb\nheadroom infrastructure\") dropped the skb_reset_*_header() calls that\nused to be there.  skb_mac_header() is then 0xFFFF, the length becomes\na large negative number and skb_push() reports it through\nskb_under_panic() -- from softirq context, so it is a full system panic\neven with panic_on_oops=0:\n\n  skbuff: skb_under_panic: text:ffffffff8bd21bc1 len:-65455 put:-65471 head:... data:... tail:0x50 end:0x180 dev:can0\n  kernel BUG at net/core/skbuff.c:214!\n  RIP: 0010:skb_panic+0x50/0x60\n  Call Trace:\n   <IRQ>\n   skb_push+0x38/0x40\n   packet_rcv_spkt+0xe1/0x170\n   __netif_receive_skb_core.constprop.0+0x7e8/0xd30\n   ...\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe socket type is reachable: packet_create() accepts SOCK_PACKET\nalongside SOCK_RAW and SOCK_DGRAM behind the same CAP_NET_RAW check,\nand neither the socket length nor a capability check keeps it away\nfrom a CAN interface.\n\nThe missing skb_reset_*_header() calls in init_can_skb() are a\nregression in their own right and are being fixed separately, but a\npacket socket should not turn a link layer that did not initialise its\nmac header into a kernel panic.  Guard the push the way the other two\nreceive paths do.\n\nTested on v7.3-rc5 under QEMU with a slcan device on a pty, which is\nthe driver RX path: vcan does not reproduce it, because can_send()\nresets the headers on the way out.  One SOCK_PACKET socket bound to\ncan0 and one frame written into the line discipline panics an\nunpatched kernel with the trace above; the same image with this patch\nprints no panic and powers off normally.  Both kernels are this tree,\ndefconfig plus CONFIG_CAN_SLCAN=y, differing only in this hunk.","Type":"Description","Title":"net/packet: guard the ll header push in packet_rcv_spkt()"}]}}}