{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "bd9d6a3efa9709e653aafbeb859289feccb8e70c"
            },
            {
              "fixed": "58bcdfb2b2e412088839ae740b1a95154dc0b8d0"
            },
            {
              "fixed": "e879148867bd4c4cac42e063ffaffa187dddc6fe"
            },
            {
              "fixed": "c1a4f7b1848f95302df598217e1c7a1410c2d0c5"
            },
            {
              "fixed": "ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "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-2026-89691.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: clear opcnt on compound arg release to prevent OOB read\n\nnfsd4_release_compoundargs() resets args-\u003eops to the inline iops[8]\narray when the dynamically-allocated ops buffer is freed, but leaves\nargs-\u003eopcnt at its original value (which can be up to 200 for NFSv4.1+\ncompounds).\n\nIf rq_status_counter is stuck at an odd value (which can happen when\nnfsd_dispatch() hits an error path after setting it odd), the RPC\nstatus dumpit handler reads min(opcnt, 16) entries from args-\u003eops[].\nSince iops only has 8 elements and is the last field in struct\nnfsd4_compoundargs, reading indices 8-15 accesses adjacent slab memory\nand leaks it to userspace via netlink.\n\nZero opcnt unconditionally in nfsd4_release_compoundargs() so stale\ncompound metadata is never exposed through the status interface.\n\n[ cel: Remove the kvfree_rcu_mightsleep() sleep from the exposure window ]",
  "id": "CVE-2026-89691",
  "modified": "2026-09-13T03:30:15.892734200Z",
  "published": "2026-09-11T19:46:11.284Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/58bcdfb2b2e412088839ae740b1a95154dc0b8d0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ae4c38555e81563b8dc5eae55ffd70f0ea97aa5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c1a4f7b1848f95302df598217e1c7a1410c2d0c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e879148867bd4c4cac42e063ffaffa187dddc6fe"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89691.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89691"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "nfsd: clear opcnt on compound arg release to prevent OOB read"
}