{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-80637", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.777Z", "datePublished": "2026-08-28T06:48:50.836Z", "dateUpdated": "2026-10-21T12:46:42.681Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:46:42.681Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: synproxy: fix unaligned memory access in timestamp adjustment\n\nUse get_unaligned_be32() and put_unaligned_be32() to safely read and\nwrite the timestamp fields. This prevents performance degradation due to\nunaligned memory access or even a crash on strict alignment\narchitectures.\n\nThis follows the implementation of timestamp parsing in the networking\nstack at tcp_parse_options() and synproxy_parse_options()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - synproxy_tstamp_adjust() runs in ipv4/ipv6_synproxy_hook on received TCP segments after SYNPROXY handshake; internet-facing gateways with SYNPROXY enabled process attacker-crafted inbound packets, matching CNA precedent for remote synproxy packet bugs.\nAC:L - Once SYNPROXY with timestamps is active and tsoff is set, the attacker fully controls TCP option layout and can reliably place TCPOPT_TIMESTAMP so op[2]/op[6] are 2-mod-4 unaligned (e.g. MSS+SACK_PERM+two NOPs+TIMESTAMP), deterministically hitting the misaligned __be32 access.\nPR:N - Exploitation requires only sending TCP traffic to a host where an administrator already enabled SYNPROXY/nftables synproxy with timestamps; the remote attacker needs no local account, capability, or authentication on the target.\nUI:N - The netfilter hook processes matching TCP segments automatically during normal connection handling; no victim user action beyond routine network connectivity to the protected service is required.\nS:U - An alignment fault in synproxy timestamp adjustment panics or oopses the host kernel but does not cross VM, container, IOMMU, or other security boundaries; impact remains within the same kernel authority.\nC:N - The flaw is misaligned load/store of the packet's own TCP timestamp fields inside the skb buffer, not an out-of-bounds or use-after-free read of kernel memory; on strict-alignment architectures it faults immediately without disclosing attacker-inaccessible data.\nI:N - No kernel metadata or adjacent structures are corrupted; the write only adjusts the intended timestamp value in the TCP option bytes, and strict-alignment targets fault before any unintended modification can occur.\nA:H - The commit and fault mechanism confirm that direct misaligned __be32 dereference on strict-alignment architectures (e.g. SPARC, some ARM) causes a kernel alignment fault/oops/panic, fully denying availability on SYNPROXY-protected gateways and embedded routers." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_synproxy_core.c" ], "versions": [ { "version": "48b1de4c110a7afa4b85862f6c75af817db26fad", "lessThan": "95cda0446f51077c343fdd8264be2737eb25a6c3", "status": "affected", "versionType": "git" }, { "version": "48b1de4c110a7afa4b85862f6c75af817db26fad", "lessThan": "2b8e7aaa38002d8ee2f48d87b1f392eadd8e98c4", "status": "affected", "versionType": "git" }, { "version": "48b1de4c110a7afa4b85862f6c75af817db26fad", "lessThan": "5c9c67cf7a3d16051dfb90e98836f530964dfb8e", "status": "affected", "versionType": "git" }, { "version": "48b1de4c110a7afa4b85862f6c75af817db26fad", "lessThan": "ea3d2caa5bfacf5db5c1cad521ca5d9144edd9a7", "status": "affected", "versionType": "git" }, { "version": "48b1de4c110a7afa4b85862f6c75af817db26fad", "lessThan": "992c20bc8a4aba220c8b95b467d049289778dad6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_synproxy_core.c" ], "versions": [ { "version": "3.12", "status": "affected" }, { "version": "0", "lessThan": "3.12", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.12", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/95cda0446f51077c343fdd8264be2737eb25a6c3" }, { "url": "https://git.kernel.org/stable/c/2b8e7aaa38002d8ee2f48d87b1f392eadd8e98c4" }, { "url": "https://git.kernel.org/stable/c/5c9c67cf7a3d16051dfb90e98836f530964dfb8e" }, { "url": "https://git.kernel.org/stable/c/ea3d2caa5bfacf5db5c1cad521ca5d9144edd9a7" }, { "url": "https://git.kernel.org/stable/c/992c20bc8a4aba220c8b95b467d049289778dad6" } ], "title": "netfilter: synproxy: fix unaligned memory access in timestamp adjustment", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-80637", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:19:14.142885Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:31.587Z" } } ] } }