{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64531", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.794Z", "datePublished": "2026-07-27T06:32:32.596Z", "dateUpdated": "2026-08-22T04:12:18.141Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:08.992Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject oversized nested action attrs\n\nOpen vSwitch stores generated flow actions as nlattrs, whose nla_len\nfield is u16. Commit a1e64addf3ff (\"net: openvswitch: remove\nmisbehaving actions length check\") allowed the total sw_flow_actions\nstream to grow beyond 64 KiB, which is valid, but also removed the last\nguard preventing a generated nested action attribute from exceeding\nU16_MAX.\n\nAn oversized generated container can thus be closed with a truncated\nnla_len. A later dump or teardown then walks a structurally different\nstream than the one that was validated. In particular, an oversized\nnested CLONE/CT action may cause subsequent bytes in the generated\nstream to be interpreted as independent actions.\n\nKeep the larger total-action-stream behavior, but make nested action\nclose reject generated containers that do not fit in nla_len, and return\nthe error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and\nCHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse\nconstruction order before discarding failed wrappers, so resources copied\ninto the rejected tails are released before the wrappers are removed.\n\nMost failed outer wrappers are discarded by truncating actions_len after\nchild resources have been released. CHECK_PKT_LEN also trims its parent\nafter branch resources are gone. SET/TUNNEL close failures unwind their\nknown tun_dst ownership directly, and SET_TO_MASKED has no external\nownership and truncates on close failure." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable action builder is reached through local Generic Netlink requests such as OVS_FLOW_CMD_NEW or OVS_PACKET_CMD_EXECUTE. Remote packets cannot construct the malformed action stream.\nAC:L - The attacker deterministically controls the nested-action expansion, wrapped length, and resulting parser alignment; no race or uncontrollable condition is required.\nPR:L - The operations require CAP_NET_ADMIN but use GENL_UNS_ADMIN_PERM in namespace-aware families. An unprivileged user can obtain the required capability through an allowed user and network namespace.\nUI:N - Once the attacker sends the crafted netlink request, vulnerable dumping, teardown, or execution occurs without another user's participation.\nS:U - The vulnerability and its effects remain within the host kernel's security authority. Kernel privilege escalation from a user namespace does not constitute a CVSS scope change.\nC:H - Length truncation can reinterpret attacker-controlled userdata as an internal SET or CT action. The dump path can consequently dereference an attacker-selected kernel pointer and serialize referenced memory.\nI:H - Fake SET or CT actions can make execution or teardown perform reference-count operations, releases, and frees through attacker-controlled pointers. This provides exploitable memory-corruption primitives capable of kernel code execution.\nA:H - Attacker-controlled invalid pointers can cause a kernel oops or panic, while zero-length misparsed actions can cause a non-advancing execution loop and soft lockup." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/openvswitch/flow_netlink.c" ], "versions": [ { "version": "057dbc5b72e9fcac439cd561c3a539b8a0edeb92", "lessThan": "ab855641241387db062a5e41d9ad6b8561542572", "status": "affected", "versionType": "git" }, { "version": "2532adbfe917c0e71dba2650ffc6efe396314c87", "lessThan": "c66bd2626c2764f23764ff0f8277f44a9cfe8349", "status": "affected", "versionType": "git" }, { "version": "4b1a0ee6164c7204c68ab5a9c48c07bfe8852485", "lessThan": "d573250d228401f707f4dbc09d11227a6215ee5f", "status": "affected", "versionType": "git" }, { "version": "e6610f9c08b4c04cf7949c10fc246c071d00e935", "lessThan": "f1efff8858403191361a01269c6fe8dd7f55a385", "status": "affected", "versionType": "git" }, { "version": "a1e64addf3ff9257b45b78bc7d743781c3f41340", "lessThan": "dbd14f736be02cfe73049bd801af89becd1a0749", "status": "affected", "versionType": "git" }, { "version": "a1e64addf3ff9257b45b78bc7d743781c3f41340", "lessThan": "1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe", "status": "affected", "versionType": "git" }, { "version": "a1e64addf3ff9257b45b78bc7d743781c3f41340", "lessThan": "3f1f755366687d051174739fb99f7d560202f60b", "status": "affected", "versionType": "git" }, { "version": "6b099d285d7ed324494b6d684f377aa103856118", "status": "affected", "versionType": "git" }, { "version": "5.15.180", "lessThan": "5.15.212", "status": "affected", "versionType": "semver" }, { "version": "6.1.132", "lessThan": "6.1.178", "status": "affected", "versionType": "semver" }, { "version": "6.6.84", "lessThan": "6.6.145", "status": "affected", "versionType": "semver" }, { "version": "6.12.20", "lessThan": "6.12.97", "status": "affected", "versionType": "semver" }, { "version": "6.13.8", "lessThan": "6.14", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/openvswitch/flow_netlink.c" ], "versions": [ { "version": "6.14", "status": "affected" }, { "version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "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": "5.15.180", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.132", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.84", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.20", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572" }, { "url": "https://git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349" }, { "url": "https://git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f" }, { "url": "https://git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385" }, { "url": "https://git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749" }, { "url": "https://git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe" }, { "url": "https://git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b" } ], "title": "net: openvswitch: reject oversized nested action attrs", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "http://www.openwall.com/lists/oss-security/2026/07/28/8" }, { "url": "http://www.openwall.com/lists/oss-security/2026/07/31/17" }, { "url": "http://www.openwall.com/lists/oss-security/2026/08/01/1" }, { "url": "http://www.openwall.com/lists/oss-security/2026/08/01/3" }, { "url": "http://www.openwall.com/lists/oss-security/2026/08/22/1" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-08-22T04:12:18.141Z" } } ] } }