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        "name": "Kernel"
      },
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  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64531.json"
  },
  "details": "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.",
  "id": "CVE-2026-64531",
  "modified": "2026-08-18T03:31:25.971712258Z",
  "published": "2026-07-27T06:32:32.596Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/28/8"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/31/17"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/01/1"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/08/01/3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64531.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64531"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "net: openvswitch: reject oversized nested action attrs"
}