{"api_version":"1","generated_at":"2026-08-22T21:52:58+00:00","cve":"CVE-2026-74714","urls":{"html":"https://cve.report/CVE-2026-74714","api":"https://cve.report/api/cve/CVE-2026-74714.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74714","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74714"},"summary":{"title":"bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()\n\nreqsk_queue_hash_req() publishes a TCP_NEW_SYN_RECV request_sock onto\nthe ehash chain, drops the bucket lock, and only afterwards sets\nrsk_refcnt to 3.\n\nLockless readers such as __inet_lookup_established() handle this with\nrefcount_inc_not_zero(), but bpf_iter_tcp_established_batch() uses plain\nsock_hold() while holding the bucket lock, on the assumption that the\nlock guarantees sk_refcnt > 0. That assumption does not hold for\nrequest_sock:\n\n  CPU 0                                CPU 1\n  -----                                -----\n  tcp_conn_request()\n   reqsk_queue_hash_req()\n    inet_ehash_insert(req)\n     spin_lock(bucket)\n     __sk_nulls_add_node_rcu(req)      // rsk_refcnt == 0\n     spin_unlock(bucket)\n                                       bpf_iter_tcp_established_batch()\n                                        spin_lock(bucket)\n                                        sock_hold(req)   <-- addition on 0\n                                        spin_unlock(bucket)\n    refcount_set(&req->rsk_refcnt, 3)  // clobbers saturated value\n\nwhich surfaces as:\n\n  refcount_t: addition on 0; use-after-free.\n  WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x48/0x90, CPU#1\n  Call Trace:\n   bpf_iter_tcp_established_batch+0x14e/0x170\n   bpf_iter_tcp_batch+0x53/0x200\n   bpf_iter_tcp_seq_next+0x27/0x70\n   bpf_seq_read+0x107/0x410\n   vfs_read+0xb9/0x380\n\nThe iterator's stolen reference is lost when the publishing CPU's\nrefcount_set() overwrites the count, leaving the socket one reference\nshort. When the last legitimate owner drops its reference the reqsk is\nfreed while still reachable, leading to use-after-free.\n\nThis reproduces in seconds with tcp_syncookies=0, a handful of threads\ndoing connect()/close() to a local listener while others read an\niter/tcp link in a tight loop.\n\nUse refcount_inc_not_zero() and skip the socket on failure. A skipped\nsocket is still part of the bucket, so keep counting it in expected.\nThe reallocations are sized from expected, and a request sock whose\nrefcount gets published while the lock is held across the last realloc\nmust already have room.\n\nA skipped socket is counted in expected but never batched, so end_sk\ncan be short of expected on a batch that is actually complete. Decide\ncompleteness by whether the walk left any socket behind instead. The\nWARN after the locked realloc checks the same, replacing an\nend_sk == expected check that could not hold on that path since\ncommit cdec67a489d4 (\"bpf: tcp: Make sure iter->batch always\ncontains a full bucket snapshot\").\n\nIf every matching socket in a bucket is mid-init (refcount 0), end_sk\nstays 0. Advance to the next bucket rather than returning a batch entry\nthat was never filled this round.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:46","updated_at":"2026-08-22 16:16:46"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/97e74d3e45d653c07c2d406fc530a9bbe3df8396","name":"https://git.kernel.org/stable/c/97e74d3e45d653c07c2d406fc530a9bbe3df8396","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cc0295f89296ed351fc4b0b48fee887ba02c5d24","name":"https://git.kernel.org/stable/c/cc0295f89296ed351fc4b0b48fee887ba02c5d24","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cefcbbe20846a45f9a7dae868f7ef1000953e2df","name":"https://git.kernel.org/stable/c/cefcbbe20846a45f9a7dae868f7ef1000953e2df","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e5fd3f514e27db1f05fbd72ba615d74941e23c51","name":"https://git.kernel.org/stable/c/e5fd3f514e27db1f05fbd72ba615d74941e23c51","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7d2b60a4bc0499f62ff8520af6309bbe170882fd","name":"https://git.kernel.org/stable/c/7d2b60a4bc0499f62ff8520af6309bbe170882fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ddbe966b5d1fe212ada749bc3d0b410f1a7dea74","name":"https://git.kernel.org/stable/c/ddbe966b5d1fe212ada749bc3d0b410f1a7dea74","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74714","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74714","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 cc0295f89296ed351fc4b0b48fee887ba02c5d24 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 ddbe966b5d1fe212ada749bc3d0b410f1a7dea74 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 7d2b60a4bc0499f62ff8520af6309bbe170882fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 cefcbbe20846a45f9a7dae868f7ef1000953e2df git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 97e74d3e45d653c07c2d406fc530a9bbe3df8396 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 04c7820b776f1c4b48698574c47de9e940d368e8 e5fd3f514e27db1f05fbd72ba615d74941e23c51 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.183 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.152 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.104 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * 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/ipv4/tcp_ipv4.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"cc0295f89296ed351fc4b0b48fee887ba02c5d24","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"},{"lessThan":"ddbe966b5d1fe212ada749bc3d0b410f1a7dea74","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"},{"lessThan":"7d2b60a4bc0499f62ff8520af6309bbe170882fd","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"},{"lessThan":"cefcbbe20846a45f9a7dae868f7ef1000953e2df","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"},{"lessThan":"97e74d3e45d653c07c2d406fc530a9bbe3df8396","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"},{"lessThan":"e5fd3f514e27db1f05fbd72ba615d74941e23c51","status":"affected","version":"04c7820b776f1c4b48698574c47de9e940d368e8","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/tcp_ipv4.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.15"},{"lessThan":"5.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.183","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.152","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.104","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.183","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.152","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.104","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.45","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()\n\nreqsk_queue_hash_req() publishes a TCP_NEW_SYN_RECV request_sock onto\nthe ehash chain, drops the bucket lock, and only afterwards sets\nrsk_refcnt to 3.\n\nLockless readers such as __inet_lookup_established() handle this with\nrefcount_inc_not_zero(), but bpf_iter_tcp_established_batch() uses plain\nsock_hold() while holding the bucket lock, on the assumption that the\nlock guarantees sk_refcnt > 0. That assumption does not hold for\nrequest_sock:\n\n  CPU 0                                CPU 1\n  -----                                -----\n  tcp_conn_request()\n   reqsk_queue_hash_req()\n    inet_ehash_insert(req)\n     spin_lock(bucket)\n     __sk_nulls_add_node_rcu(req)      // rsk_refcnt == 0\n     spin_unlock(bucket)\n                                       bpf_iter_tcp_established_batch()\n                                        spin_lock(bucket)\n                                        sock_hold(req)   <-- addition on 0\n                                        spin_unlock(bucket)\n    refcount_set(&req->rsk_refcnt, 3)  // clobbers saturated value\n\nwhich surfaces as:\n\n  refcount_t: addition on 0; use-after-free.\n  WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x48/0x90, CPU#1\n  Call Trace:\n   bpf_iter_tcp_established_batch+0x14e/0x170\n   bpf_iter_tcp_batch+0x53/0x200\n   bpf_iter_tcp_seq_next+0x27/0x70\n   bpf_seq_read+0x107/0x410\n   vfs_read+0xb9/0x380\n\nThe iterator's stolen reference is lost when the publishing CPU's\nrefcount_set() overwrites the count, leaving the socket one reference\nshort. When the last legitimate owner drops its reference the reqsk is\nfreed while still reachable, leading to use-after-free.\n\nThis reproduces in seconds with tcp_syncookies=0, a handful of threads\ndoing connect()/close() to a local listener while others read an\niter/tcp link in a tight loop.\n\nUse refcount_inc_not_zero() and skip the socket on failure. A skipped\nsocket is still part of the bucket, so keep counting it in expected.\nThe reallocations are sized from expected, and a request sock whose\nrefcount gets published while the lock is held across the last realloc\nmust already have room.\n\nA skipped socket is counted in expected but never batched, so end_sk\ncan be short of expected on a batch that is actually complete. Decide\ncompleteness by whether the walk left any socket behind instead. The\nWARN after the locked realloc checks the same, replacing an\nend_sk == expected check that could not hold on that path since\ncommit cdec67a489d4 (\"bpf: tcp: Make sure iter->batch always\ncontains a full bucket snapshot\").\n\nIf every matching socket in a bucket is mid-init (refcount 0), end_sk\nstays 0. Advance to the next bucket rather than returning a batch entry\nthat was never filled this round."}],"providerMetadata":{"dateUpdated":"2026-08-22T15:33:09.643Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/cc0295f89296ed351fc4b0b48fee887ba02c5d24"},{"url":"https://git.kernel.org/stable/c/ddbe966b5d1fe212ada749bc3d0b410f1a7dea74"},{"url":"https://git.kernel.org/stable/c/7d2b60a4bc0499f62ff8520af6309bbe170882fd"},{"url":"https://git.kernel.org/stable/c/cefcbbe20846a45f9a7dae868f7ef1000953e2df"},{"url":"https://git.kernel.org/stable/c/97e74d3e45d653c07c2d406fc530a9bbe3df8396"},{"url":"https://git.kernel.org/stable/c/e5fd3f514e27db1f05fbd72ba615d74941e23c51"}],"title":"bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74714","datePublished":"2026-08-22T15:33:09.643Z","dateReserved":"2026-08-15T05:44:03.928Z","dateUpdated":"2026-08-22T15:33:09.643Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:46","lastModifiedDate":"2026-08-22 16:16:46","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74714","Ordinal":"1","Title":"bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()","CVE":"CVE-2026-74714","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74714","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()\n\nreqsk_queue_hash_req() publishes a TCP_NEW_SYN_RECV request_sock onto\nthe ehash chain, drops the bucket lock, and only afterwards sets\nrsk_refcnt to 3.\n\nLockless readers such as __inet_lookup_established() handle this with\nrefcount_inc_not_zero(), but bpf_iter_tcp_established_batch() uses plain\nsock_hold() while holding the bucket lock, on the assumption that the\nlock guarantees sk_refcnt > 0. That assumption does not hold for\nrequest_sock:\n\n  CPU 0                                CPU 1\n  -----                                -----\n  tcp_conn_request()\n   reqsk_queue_hash_req()\n    inet_ehash_insert(req)\n     spin_lock(bucket)\n     __sk_nulls_add_node_rcu(req)      // rsk_refcnt == 0\n     spin_unlock(bucket)\n                                       bpf_iter_tcp_established_batch()\n                                        spin_lock(bucket)\n                                        sock_hold(req)   <-- addition on 0\n                                        spin_unlock(bucket)\n    refcount_set(&req->rsk_refcnt, 3)  // clobbers saturated value\n\nwhich surfaces as:\n\n  refcount_t: addition on 0; use-after-free.\n  WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x48/0x90, CPU#1\n  Call Trace:\n   bpf_iter_tcp_established_batch+0x14e/0x170\n   bpf_iter_tcp_batch+0x53/0x200\n   bpf_iter_tcp_seq_next+0x27/0x70\n   bpf_seq_read+0x107/0x410\n   vfs_read+0xb9/0x380\n\nThe iterator's stolen reference is lost when the publishing CPU's\nrefcount_set() overwrites the count, leaving the socket one reference\nshort. When the last legitimate owner drops its reference the reqsk is\nfreed while still reachable, leading to use-after-free.\n\nThis reproduces in seconds with tcp_syncookies=0, a handful of threads\ndoing connect()/close() to a local listener while others read an\niter/tcp link in a tight loop.\n\nUse refcount_inc_not_zero() and skip the socket on failure. A skipped\nsocket is still part of the bucket, so keep counting it in expected.\nThe reallocations are sized from expected, and a request sock whose\nrefcount gets published while the lock is held across the last realloc\nmust already have room.\n\nA skipped socket is counted in expected but never batched, so end_sk\ncan be short of expected on a batch that is actually complete. Decide\ncompleteness by whether the walk left any socket behind instead. The\nWARN after the locked realloc checks the same, replacing an\nend_sk == expected check that could not hold on that path since\ncommit cdec67a489d4 (\"bpf: tcp: Make sure iter->batch always\ncontains a full bucket snapshot\").\n\nIf every matching socket in a bucket is mid-init (refcount 0), end_sk\nstays 0. Advance to the next bucket rather than returning a batch entry\nthat was never filled this round.","Type":"Description","Title":"bpf: tcp: Fix use-after-free in bpf_iter_tcp_established_batch()"}]}}}