CVE-2025-39894

{"id": "CVE-2025-39894", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-39894", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-15T21:54:35.991421Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "7c3f28599652acf431a2211168de4a583f30b6d5", "lessThan": "d00c8b0daf56012f69075e3377da67878c775e4c", "versionType": "git"}, {"status": "affected", "version": "2b1414d5e94e477edff1d2c79030f1d742625ea0", "lessThan": "ccbad4803225eafe0175d3cb19f0d8d73b504a94", "versionType": "git"}, {"status": "affected", "version": "80cd0487f630b5382734997c3e5e3003a77db315", "lessThan": "50db11e2bbb635e38e3dd096215580d6adb41fb0", "versionType": "git"}, {"status": "affected", "version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9", "lessThan": "c47ca77fee9071aa543bae592dd2a384f895c8b6", "versionType": "git"}, {"status": "affected", "version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9", "lessThan": "a74abcf0f09f59daeecf7a3ba9c1d690808b0afe", "versionType": "git"}, {"status": "affected", "version": "62e7151ae3eb465e0ab52a20c941ff33bb6332e9", "lessThan": "479a54ab92087318514c82428a87af2d7af1a576", "versionType": "git"}, {"status": "affected", "version": "cb734975b0ffa688ff6cc0eed463865bf07b6c01", "versionType": "git"}, {"status": "affected", "version": "5.15.151", "lessThan": "5.15.192", "versionType": "semver"}, {"status": "affected", "version": "6.1.81", "lessThan": "6.1.151", "versionType": "semver"}, {"status": "affected", "version": "6.6.21", "lessThan": "6.6.105", "versionType": "semver"}, {"status": "affected", "version": "6.7.9", "lessThan": "6.8", "versionType": "semver"}], "programFiles": ["net/bridge/br_netfilter_hooks.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.8"}, {"status": "unaffected", "version": "0", "lessThan": "6.8", "versionType": "semver"}, {"status": "unaffected", "version": "5.15.192", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.151", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.105", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.46", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.16.6", "versionType": "semver", "lessThanOrEqual": "6.16.*"}, {"status": "unaffected", "version": "6.17", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/bridge/br_netfilter_hooks.c"], "defaultStatus": "affected"}]}], "published": "2025-10-01T08:15:31.987", "references": [{"url": "https://git.kernel.org/stable/c/479a54ab92087318514c82428a87af2d7af1a576", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/50db11e2bbb635e38e3dd096215580d6adb41fb0", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a74abcf0f09f59daeecf7a3ba9c1d690808b0afe", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/c47ca77fee9071aa543bae592dd2a384f895c8b6", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ccbad4803225eafe0175d3cb19f0d8d73b504a94", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d00c8b0daf56012f69075e3377da67878c775e4c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html", "tags": ["Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: br_netfilter: do not check confirmed bit in br_nf_local_in() after confirm\n\nWhen send a broadcast packet to a tap device, which was added to a bridge,\nbr_nf_local_in() is called to confirm the conntrack. If another conntrack\nwith the same hash value is added to the hash table, which can be\ntriggered by a normal packet to a non-bridge device, the below warning\nmay happen.\n\n ------------[ cut here ]------------\n WARNING: CPU: 1 PID: 96 at net/bridge/br_netfilter_hooks.c:632 br_nf_local_in+0x168/0x200\n CPU: 1 UID: 0 PID: 96 Comm: tap_send Not tainted 6.17.0-rc2-dirty #44 PREEMPT(voluntary)\n RIP: 0010:br_nf_local_in+0x168/0x200\n Call Trace:\n <TASK>\n nf_hook_slow+0x3e/0xf0\n br_pass_frame_up+0x103/0x180\n br_handle_frame_finish+0x2de/0x5b0\n br_nf_hook_thresh+0xc0/0x120\n br_nf_pre_routing_finish+0x168/0x3a0\n br_nf_pre_routing+0x237/0x5e0\n br_handle_frame+0x1ec/0x3c0\n __netif_receive_skb_core+0x225/0x1210\n __netif_receive_skb_one_core+0x37/0xa0\n netif_receive_skb+0x36/0x160\n tun_get_user+0xa54/0x10c0\n tun_chr_write_iter+0x65/0xb0\n vfs_write+0x305/0x410\n ksys_write+0x60/0xd0\n do_syscall_64+0xa4/0x260\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n </TASK>\n ---[ end trace 0000000000000000 ]---\n\nTo solve the hash conflict, nf_ct_resolve_clash() try to merge the\nconntracks, and update skb->_nfct. However, br_nf_local_in() still use the\nold ct from local variable 'nfct' after confirm(), which leads to this\nwarning.\n\nIf confirm() does not insert the conntrack entry and return NF_DROP, the\nwarning may also occur. There is no need to reserve the WARN_ON_ONCE, just\nremove it."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnetfilter: br_netfilter: no verificar el bit confirmado en br_nf_local_in() despu\u00e9s de confirmar\n\nCuando se env\u00eda un paquete de difusi\u00f3n a un dispositivo tap, que fue a\u00f1adido a un puente, se llama a br_nf_local_in() para confirmar el conntrack. Si otro conntrack con el mismo valor hash es a\u00f1adido a la tabla hash, lo cual puede ser provocado por un paquete normal a un dispositivo que no es un puente, la siguiente advertencia puede ocurrir.\n\n ------------[ cut here ]------------\n WARNING: CPU: 1 PID: 96 at net/bridge/br_netfilter_hooks.c:632 br_nf_local_in+0x168/0x200\n CPU: 1 UID: 0 PID: 96 Comm: tap_send Not tainted 6.17.0-rc2-dirty #44 PREEMPT(voluntary)\n RIP: 0010:br_nf_local_in+0x168/0x200\n Call Trace:\n <TASK>\n nf_hook_slow+0x3e/0xf0\n br_pass_frame_up+0x103/0x180\n br_handle_frame_finish+0x2de/0x5b0\n br_nf_hook_thresh+0xc0/0x120\n br_nf_pre_routing_finish+0x168/0x3a0\n br_nf_pre_routing+0x237/0x5e0\n br_handle_frame+0x1ec/0x3c0\n __netif_receive_skb_core+0x225/0x1210\n __netif_receive_skb_one_core+0x37/0xa0\n netif_receive_skb+0x36/0x160\n tun_get_user+0xa54/0x10c0\n tun_chr_write_iter+0x65/0xb0\n vfs_write+0x305/0x410\n ksys_write+0x60/0xd0\n do_syscall_64+0xa4/0x260\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n </TASK>\n ---[ end trace 0000000000000000 ]---\n\nPara resolver el conflicto de hash, nf_ct_resolve_clash() intenta fusionar los conntracks y actualizar skb->_nfct. Sin embargo, br_nf_local_in() todav\u00eda usa el ct antiguo de la variable local 'nfct' despu\u00e9s de confirm(), lo que lleva a esta advertencia.\n\nSi confirm() no inserta la entrada de conntrack y devuelve NF_DROP, la advertencia tambi\u00e9n puede ocurrir. No hay necesidad de reservar el WARN_ON_ONCE, simplemente qu\u00edtalo."}], "lastModified": "2026-10-19T21:10:00.160", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "EAEDCA1A-2745-4005-85AE-39E44436B5D2", "versionEndExcluding": "5.15.192", "versionStartIncluding": "5.15.151"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CB3C782A-F7CE-4C5F-AA7F-B5FF3DCDA1AF", "versionEndExcluding": "6.1.151", "versionStartIncluding": "6.1.81"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "224C8BB6-3C4A-4887-98F0-6563C9376380", "versionEndExcluding": "6.6.105", "versionStartIncluding": "6.6.21"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "739125EE-99C1-42E1-B870-04FD5010BA66", "versionEndExcluding": "6.8", "versionStartIncluding": "6.7.9"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E12DFF9A-7ACE-4914-8CB1-28DB75F1E42B", "versionEndExcluding": "6.12.46", "versionStartIncluding": "6.8.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "548F104C-0F08-438B-9C97-64C903F0C678", "versionEndExcluding": "6.16.6", "versionStartIncluding": "6.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:-:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "41E47F32-BA80-4333-96FD-4D25082B0FDD"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc7:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C9B8A5CE-6D20-4C36-AC01-ACA4B70003A8"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "39982C4B-716E-4B2F-8196-FA301F47807D"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "340BEEA9-D70D-4290-B502-FBB1032353B1"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}