{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c"
            },
            {
              "fixed": "24806fc9bca28fa1433bf938d1424dcb45d80e50"
            },
            {
              "fixed": "9a5c2700336878465a630804a2d21864f22eca9c"
            },
            {
              "fixed": "b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d"
            },
            {
              "fixed": "305f1828b871dd46bf41addeb6f11d2c162dcb25"
            },
            {
              "fixed": "f99399b48e3edd6851fac34cd329bab9f1f33baf"
            },
            {
              "fixed": "11516a0c402a6c1fa52254aa70d8d65fb921e59e"
            },
            {
              "fixed": "da0b595d8e6e2dd798f6e34e09dc51a13b888514"
            },
            {
              "fixed": "dd3ea3fcba7c75493760cdbccd35f029597e8d5e"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.7.0"
            },
            {
              "fixed": "5.10.273"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.224"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.191"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.160"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.113"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.57"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99040.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKEYS: Fix add_key() race with keyring restriction\n\n__key_create_or_update() snapshots keyring-\u003erestrict_link before taking\nthe destination keyring's semaphore.  keyring_restrict() installs a\nrestriction while holding that semaphore.\n\nThis allows a writer to observe no restriction, wait for the keyring\nowner to install a reject-all restriction and return successfully, and\nthen link a key using the stale NULL snapshot.  The writer only needs\nwrite permission on the destination keyring.\n\nMove the restrict_link read after __key_link_lock() and\n__key_link_begin().  The read and the subsequent restriction check are\nthen serialized with restriction installation by keyring-\u003esem.\n\nThe race was reproduced on v7.2.8 in 19 executions where restriction\ninstallation returned before the link completed.  All 19 linked the key\ndespite the reject-all restriction.  With this change, 312 executions\nreached the same ordering and every add_key() call failed with -EPERM.\n\nThe issue was found by manual concurrency analysis assisted by AI-based\nanalysis and independently verified with a QEMU reproducer and kernel\ninstrumentation.",
  "id": "CVE-2026-99040",
  "modified": "2026-11-01T02:30:36.458143841Z",
  "published": "2026-10-23T12:21:59.288Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/11516a0c402a6c1fa52254aa70d8d65fb921e59e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24806fc9bca28fa1433bf938d1424dcb45d80e50"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/305f1828b871dd46bf41addeb6f11d2c162dcb25"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9a5c2700336878465a630804a2d21864f22eca9c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/da0b595d8e6e2dd798f6e34e09dc51a13b888514"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dd3ea3fcba7c75493760cdbccd35f029597e8d5e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f99399b48e3edd6851fac34cd329bab9f1f33baf"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99040.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99040"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.2",
  "summary": "KEYS: Fix add_key() race with keyring restriction"
}