{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05"
            },
            {
              "fixed": "5b3a7d7c23c071efe12dd1bc1d2e5f97c4892921"
            },
            {
              "fixed": "8215892993ea9f5231da4fa9eb42428a286fce8b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89664.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: release OPEN-decoded posix ACLs via op_release\n\nnfsd4_decode_createhow4() calls nfsd4_decode_fattr4(), which allocates\nrefcounted struct posix_acl objects via posix_acl_alloc() and stores\nthem in open-\u003eop_pacl and open-\u003eop_dpacl. These pointers must be\nreleased once the OPEN compound finishes.\n\nWhen nfsd4_decode_open_claim4() returns a non-seqid-mutating error,\nthe dispatcher short-circuits before op_func runs:\n\n    nfsd4_proc_compound()\n      if (op-\u003estatus \u0026\u0026 op-\u003eopnum == OP_OPEN)\n          op-\u003estatus = nfsd4_open_omfg(...)\n              if (!seqid_mutating_err(ntohl(op-\u003estatus)))\n                  return op-\u003estatus;   /* nfsd4_open() never runs */\n      ...\n      opdesc-\u003eop_release(\u0026op-\u003eu)  /* must still release op_pacl/op_dpacl */\n\nBefore this change OP_OPEN had no .op_release in nfsd4_ops[], and the\nrelease pair lived inside nfsd4_open() at its out_err: label. On the\nshort-circuit path nfsd4_open() is never invoked, so both posix_acl\nrefs leak on every malformed OPEN compound that carries valid POSIX\nACL createhow4 attributes.\n\nAdd nfsd4_open_release() and wire it as .op_release for OP_OPEN.\nposix_acl_release() is NULL-safe, so the single release site covers\nboth the normal path and the nfsd4_open_omfg short-circuit. Remove\nthe matching posix_acl_release() pair from nfsd4_open()'s out_err:\nlabel to avoid double-releasing.\n\nThe compound loop has two encoding branches: nfsd4_encode_operation()\nfor normal ops, and nfsd4_encode_replay() for v4.0 replayed ops.\nop_release was only called from nfsd4_encode_operation(), so resources\nattached to op-\u003eu leak on the replay path.\n\nMove the op_release() call out of nfsd4_encode_operation() and the\nreplay branch, placing it after the if-else in nfsd4_proc_compound().\nThis gives a single call site in a fairly obviously-correct place,\ncovering both the normal encoding and replay paths.",
  "id": "CVE-2026-89664",
  "modified": "2026-09-15T03:31:07.532299668Z",
  "published": "2026-09-11T19:45:51.319Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5b3a7d7c23c071efe12dd1bc1d2e5f97c4892921"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8215892993ea9f5231da4fa9eb42428a286fce8b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89664.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89664"
    },
    {
      "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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "nfsd: release OPEN-decoded posix ACLs via op_release"
}