{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31685", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.131Z", "datePublished": "2026-04-25T08:47:02.857Z", "dateUpdated": "2026-08-05T12:24:29.973Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:29.973Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ip6t_eui64: reject invalid MAC header for all packets\n\n`eui64_mt6()` derives a modified EUI-64 from the Ethernet source address\nand compares it with the low 64 bits of the IPv6 source address.\n\nThe existing guard only rejects an invalid MAC header when\n`par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()`\ncan still reach `eth_hdr(skb)` even when the MAC header is not valid.\n\nFix this by removing the `par->fragoff != 0` condition so that packets\nwith an invalid MAC header are rejected before accessing `eth_hdr(skb)`." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H", "baseScore": 9.4, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable match runs from IPv6 netfilter PREROUTING/LOCAL_IN/FORWARD packet hooks, so a remote peer can reach it by sending IPv6 traffic to or through a host/router with an active eui64 xtables rule on a path with an invalid or absent Ethernet MAC header.\nAC:L - There is no race or timing requirement; the attacker can send first-fragment or non-fragment IPv6 packets with controlled header fields, and the active rule/interface combination is a deployment precondition.\nPR:N - Although installing the rule requires CAP_NET_ADMIN, in the highest-severity reasonable deployment the eui64 rule is already active and unauthenticated packets trigger the vulnerable packet path without attacker privileges.\nUI:N - No victim action is needed after the affected netfilter rule is present; packet delivery alone invokes the match.\nS:U - The impact remains within the kernel/networking security authority of the affected system and does not cross a VM, IOMMU, or similar boundary.\nC:H - With an unset or invalid MAC header, eth_hdr() can read outside the valid Ethernet header area and those bytes can influence observable netfilter behavior; following the required conservative rule for out-of-bounds reads, confidentiality is High.\nI:L - The bug can cause invalid-L2 packets to satisfy an eui64 match and bypass filtering decisions based on Ethernet-source-to-IPv6-source binding, but it does not provide a direct kernel write primitive.\nA:H - Invalid eth_hdr() access on packets with no valid MAC header can produce kernel warnings/oopses or KASAN-detected out-of-bounds accesses, and an attacker can repeat packet delivery to sustain denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/netfilter/ip6t_eui64.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "4d75bc2cd093bf5803edf512c099bfb220fd6459", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "7d6a57411caf54df025860c9b1a82cd42d57a562", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "d5603591373441fecf9951833d6d873e09320f08", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "288138418bef956f8b295751a4536c60f0e89f4a", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "9eda5478746ef7dc0e4e537b5a5e4b0ca1027091", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "807d6ee15804df6f01a35c910f09612e858739a6", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "309ae3e9a51a69699ca94eac5fac5688fa562d55", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "fdce0b3590f724540795b874b4c8850c90e6b0a8", "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/ipv6/netfilter/ip6t_eui64.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.136", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.83", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.24", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.14", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "2.6.12", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.136" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.24" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.19.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4d75bc2cd093bf5803edf512c099bfb220fd6459" }, { "url": "https://git.kernel.org/stable/c/7d6a57411caf54df025860c9b1a82cd42d57a562" }, { "url": "https://git.kernel.org/stable/c/d5603591373441fecf9951833d6d873e09320f08" }, { "url": "https://git.kernel.org/stable/c/288138418bef956f8b295751a4536c60f0e89f4a" }, { "url": "https://git.kernel.org/stable/c/9eda5478746ef7dc0e4e537b5a5e4b0ca1027091" }, { "url": "https://git.kernel.org/stable/c/807d6ee15804df6f01a35c910f09612e858739a6" }, { "url": "https://git.kernel.org/stable/c/309ae3e9a51a69699ca94eac5fac5688fa562d55" }, { "url": "https://git.kernel.org/stable/c/fdce0b3590f724540795b874b4c8850c90e6b0a8" } ], "title": "netfilter: ip6t_eui64: reject invalid MAC header for all packets", 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