{"api_version":"1","generated_at":"2026-09-11T18:41:18+00:00","cve":"CVE-2026-80849","urls":{"html":"https://cve.report/CVE-2026-80849","api":"https://cve.report/api/cve/CVE-2026-80849.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80849","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80849"},"summary":{"title":"net/tcp-ao: fix use-after-free of current_key on reconnect to another peer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-ao: fix use-after-free of current_key on reconnect to another peer\n\ntcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken,\nwith only rcu_read_lock() held. On the fast path for established\nsockets, if the rnext_keyid sent by the peer differs from\ncurrent_key->sndid, the key the peer asked for is looked up and stored\nin current_key. The lookup is inside the RCU read side, but current_key\noutlives it.\n\nWhen the socket is disconnected and connect() is called again for\nanother peer, tcp_ao_connect_init() unlinks every key that does not\nmatch the new peer and frees it with call_rcu(). If current_key points\nat such a key, it is cleared to NULL.\n\nThe fast path reads sk_state only once on entry, so a softirq that got\ninto it while the socket was still established can update current_key\nafter that loop has already run. The update is inside the RCU read side,\nso it comes before the call_rcu() callback, and once the callback frees\nthe key, current_key is left pointing at freed memory.\n\nThe next transmission picks that pointer up in tcp_get_current_key().\ntcp_ao_transmit_skb() then reads the traffic key from the freed object,\nwhich is the use-after-free.\n\nWait for one grace period before unlinking, and only if a key is going\nto be removed. By the time tcp_connect() runs the socket is already in\nTCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so\na softirq entering after the wait cannot reach the fast path, and the\nones already in it have finished. The existing NULL handling in the loop\nis then enough.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-04 16:18:13","updated_at":"2026-09-04 16:18:13"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/e54ad693eddb40c595add013f545354c538e325b","name":"https://git.kernel.org/stable/c/e54ad693eddb40c595add013f545354c538e325b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3","name":"https://git.kernel.org/stable/c/73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2857dcbd03cf3354af0fba1b65c6a260fb43811a","name":"https://git.kernel.org/stable/c/2857dcbd03cf3354af0fba1b65c6a260fb43811a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/84a93b4e012587d0a4a84ffb23ec6da18e9d85f9","name":"https://git.kernel.org/stable/c/84a93b4e012587d0a4a84ffb23ec6da18e9d85f9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/da4471557f279d0f56605158a625bb6e49ef7d41","name":"https://git.kernel.org/stable/c/da4471557f279d0f56605158a625bb6e49ef7d41","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80849","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80849","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0a3a809089eb1d4a0a2fd0c16b520d603988c859 84a93b4e012587d0a4a84ffb23ec6da18e9d85f9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0a3a809089eb1d4a0a2fd0c16b520d603988c859 73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0a3a809089eb1d4a0a2fd0c16b520d603988c859 e54ad693eddb40c595add013f545354c538e325b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0a3a809089eb1d4a0a2fd0c16b520d603988c859 2857dcbd03cf3354af0fba1b65c6a260fb43811a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 0a3a809089eb1d4a0a2fd0c16b520d603988c859 da4471557f279d0f56605158a625bb6e49ef7d41 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.7","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.108 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.49 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.13 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.3 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80849","cve":"CVE-2026-80849","epss":"0.001680000","percentile":"0.063360000","score_date":"2026-09-07","updated_at":"2026-09-08 00:05:27"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/tcp_ao.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"84a93b4e012587d0a4a84ffb23ec6da18e9d85f9","status":"affected","version":"0a3a809089eb1d4a0a2fd0c16b520d603988c859","versionType":"git"},{"lessThan":"73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3","status":"affected","version":"0a3a809089eb1d4a0a2fd0c16b520d603988c859","versionType":"git"},{"lessThan":"e54ad693eddb40c595add013f545354c538e325b","status":"affected","version":"0a3a809089eb1d4a0a2fd0c16b520d603988c859","versionType":"git"},{"lessThan":"2857dcbd03cf3354af0fba1b65c6a260fb43811a","status":"affected","version":"0a3a809089eb1d4a0a2fd0c16b520d603988c859","versionType":"git"},{"lessThan":"da4471557f279d0f56605158a625bb6e49ef7d41","status":"affected","version":"0a3a809089eb1d4a0a2fd0c16b520d603988c859","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/tcp_ao.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.7"},{"lessThan":"6.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.108","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.49","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.13","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.3","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.108","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.49","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.13","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.3","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"6.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-ao: fix use-after-free of current_key on reconnect to another peer\n\ntcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken,\nwith only rcu_read_lock() held. On the fast path for established\nsockets, if the rnext_keyid sent by the peer differs from\ncurrent_key->sndid, the key the peer asked for is looked up and stored\nin current_key. The lookup is inside the RCU read side, but current_key\noutlives it.\n\nWhen the socket is disconnected and connect() is called again for\nanother peer, tcp_ao_connect_init() unlinks every key that does not\nmatch the new peer and frees it with call_rcu(). If current_key points\nat such a key, it is cleared to NULL.\n\nThe fast path reads sk_state only once on entry, so a softirq that got\ninto it while the socket was still established can update current_key\nafter that loop has already run. The update is inside the RCU read side,\nso it comes before the call_rcu() callback, and once the callback frees\nthe key, current_key is left pointing at freed memory.\n\nThe next transmission picks that pointer up in tcp_get_current_key().\ntcp_ao_transmit_skb() then reads the traffic key from the freed object,\nwhich is the use-after-free.\n\nWait for one grace period before unlinking, and only if a key is going\nto be removed. By the time tcp_connect() runs the socket is already in\nTCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so\na softirq entering after the wait cannot reach the fast path, and the\nones already in it have finished. The existing NULL handling in the loop\nis then enough."}],"providerMetadata":{"dateUpdated":"2026-09-04T15:54:59.412Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/84a93b4e012587d0a4a84ffb23ec6da18e9d85f9"},{"url":"https://git.kernel.org/stable/c/73fde8fe4469f4ed8f0afcc0b9d6413002a9e6b3"},{"url":"https://git.kernel.org/stable/c/e54ad693eddb40c595add013f545354c538e325b"},{"url":"https://git.kernel.org/stable/c/2857dcbd03cf3354af0fba1b65c6a260fb43811a"},{"url":"https://git.kernel.org/stable/c/da4471557f279d0f56605158a625bb6e49ef7d41"}],"title":"net/tcp-ao: fix use-after-free of current_key on reconnect to another peer","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80849","datePublished":"2026-09-04T15:54:59.412Z","dateReserved":"2026-08-26T14:34:25.797Z","dateUpdated":"2026-09-04T15:54:59.412Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-04 16:18:13","lastModifiedDate":"2026-09-04 16:18:13","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80849","Ordinal":"1","Title":"net/tcp-ao: fix use-after-free of current_key on reconnect to an","CVE":"CVE-2026-80849","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80849","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-ao: fix use-after-free of current_key on reconnect to another peer\n\ntcp_inbound_ao_hash() is called before bh_lock_sock_nested() is taken,\nwith only rcu_read_lock() held. On the fast path for established\nsockets, if the rnext_keyid sent by the peer differs from\ncurrent_key->sndid, the key the peer asked for is looked up and stored\nin current_key. The lookup is inside the RCU read side, but current_key\noutlives it.\n\nWhen the socket is disconnected and connect() is called again for\nanother peer, tcp_ao_connect_init() unlinks every key that does not\nmatch the new peer and frees it with call_rcu(). If current_key points\nat such a key, it is cleared to NULL.\n\nThe fast path reads sk_state only once on entry, so a softirq that got\ninto it while the socket was still established can update current_key\nafter that loop has already run. The update is inside the RCU read side,\nso it comes before the call_rcu() callback, and once the callback frees\nthe key, current_key is left pointing at freed memory.\n\nThe next transmission picks that pointer up in tcp_get_current_key().\ntcp_ao_transmit_skb() then reads the traffic key from the freed object,\nwhich is the use-after-free.\n\nWait for one grace period before unlinking, and only if a key is going\nto be removed. By the time tcp_connect() runs the socket is already in\nTCP_SYN_SENT, and TCP_AO_ESTABLISHED does not contain TCPF_SYN_SENT, so\na softirq entering after the wait cannot reach the fast path, and the\nones already in it have finished. The existing NULL handling in the loop\nis then enough.","Type":"Description","Title":"net/tcp-ao: fix use-after-free of current_key on reconnect to an"}]}}}