FKIE_CVE-2026-99226

Vulnerability from fkie_nvd - Published: 2026-11-02 16:17 - Updated: 2026-11-03 20:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: keys: Avoid the owner account dereference in named keyring lookup Named keyring lookup must keep the storage containing the owner UID alive through the namespace mapping check. find_keyring_by_name() reads keyring->user->uid under keyring_name_lock, but that lock protects the keyring's name entry and allocation, not its separate key_user. A named session-keyring join can overlap a privileged KEYCTL_CHOWN on another CPU. If the keyring holds the last reference to its old dynamic key_user and the ownership transfer succeeds, the following ordering is possible: Named join Chown find_keyring_by_name() keyctl_chown_key() read_lock(keyring_name_lock) down_write(key->sem) load old keyring->user replace key->user and key->uid up_write(key->sem) key_put(key) key_user_put(old user): free read old user->uid read_unlock(keyring_name_lock) Chown neither takes keyring_name_lock nor key_session_mutex, so it can free the old account between the pointer load and the UID read. The lookup then reads freed memory even though the keyring itself is alive. Use keyring->uid for the mapping check. key_alloc() initializes this inline owner UID and keyctl_chown_key() updates it on chown. The existing name lock keeps its containing keyring allocated throughout the check, so lookup no longer depends on the account's lifetime. This also matches the owner UID used by the permission check. KASAN report as below: BUG: KASAN: slab-use-after-free in find_keyring_by_name+0x577/0x5d0 Read of size 4 at addr ffff8881128ae2ec by task keycase/500
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0b865fa477d94ac96c26848aab1fd176397de3f6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/40b12b93ae4ab9e22c3d571e9b09fd08afad53f6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/51409aaa01f8602552c336009fd22b226b0cdf1d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5c6a9512887a6cc694d594d9c0b57c0841d215b5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6763329f673d261641c79212abf773af77b2c922
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/77249d4b1bb5ad43552b7023c4a0978937aa7a56
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/aa03c8fb4334f14d218020f7431debf2b7766865
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b0830a26e2c3008a6e21863126b4a0e68b2761cd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c9664f780f861dd9f11f120c7a03ed0993671ebb
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/keys/keyring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "77249d4b1bb5ad43552b7023c4a0978937aa7a56",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "0b865fa477d94ac96c26848aab1fd176397de3f6",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "6763329f673d261641c79212abf773af77b2c922",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "aa03c8fb4334f14d218020f7431debf2b7766865",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "c9664f780f861dd9f11f120c7a03ed0993671ebb",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "b0830a26e2c3008a6e21863126b4a0e68b2761cd",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "5c6a9512887a6cc694d594d9c0b57c0841d215b5",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "40b12b93ae4ab9e22c3d571e9b09fd08afad53f6",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            },
            {
              "lessThan": "51409aaa01f8602552c336009fd22b226b0cdf1d",
              "status": "affected",
              "version": "2ea190d0a006ce5218baa6e798512652446a605a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "security/keys/keyring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.30"
            },
            {
              "lessThan": "2.6.30",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.161",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.115",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.60",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.3.*",
              "status": "unaffected",
              "version": "7.3.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.4-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkeys: Avoid the owner account dereference in named keyring lookup\n\nNamed keyring lookup must keep the storage containing the owner UID\nalive through the namespace mapping check.  find_keyring_by_name()\nreads keyring-\u003euser-\u003euid under keyring_name_lock, but that lock protects\nthe keyring\u0027s name entry and allocation, not its separate key_user.\n\nA named session-keyring join can overlap a privileged KEYCTL_CHOWN on\nanother CPU.  If the keyring holds the last reference to its old dynamic\nkey_user and the ownership transfer succeeds, the following ordering is\npossible:\n\n    Named join                         Chown\n    find_keyring_by_name()              keyctl_chown_key()\n      read_lock(keyring_name_lock)       down_write(key-\u003esem)\n      load old keyring-\u003euser\n                                         replace key-\u003euser and key-\u003euid\n                                         up_write(key-\u003esem)\n                                         key_put(key)\n                                         key_user_put(old user): free\n      read old user-\u003euid\n      read_unlock(keyring_name_lock)\n\nChown neither takes keyring_name_lock nor key_session_mutex, so it can\nfree the old account between the pointer load and the UID read.  The\nlookup then reads freed memory even though the keyring itself is alive.\n\nUse keyring-\u003euid for the mapping check.  key_alloc() initializes this\ninline owner UID and keyctl_chown_key() updates it on chown.\nThe existing name lock keeps its containing keyring allocated throughout\nthe check, so lookup no longer depends on the account\u0027s lifetime.  This\nalso matches the owner UID used by the permission check.\n\nKASAN report as below:\n\n    BUG: KASAN: slab-use-after-free in find_keyring_by_name+0x577/0x5d0\n    Read of size 4 at addr ffff8881128ae2ec by task keycase/500"
    }
  ],
  "id": "CVE-2026-99226",
  "lastModified": "2026-11-03T20:18:28.183",
  "metrics": {},
  "published": "2026-11-02T16:17:47.233",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0b865fa477d94ac96c26848aab1fd176397de3f6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/40b12b93ae4ab9e22c3d571e9b09fd08afad53f6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/51409aaa01f8602552c336009fd22b226b0cdf1d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5c6a9512887a6cc694d594d9c0b57c0841d215b5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6763329f673d261641c79212abf773af77b2c922"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/77249d4b1bb5ad43552b7023c4a0978937aa7a56"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aa03c8fb4334f14d218020f7431debf2b7766865"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b0830a26e2c3008a6e21863126b4a0e68b2761cd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c9664f780f861dd9f11f120c7a03ed0993671ebb"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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