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FKIE_CVE-2026-93106

Vulnerability from fkie_nvd - Published: 2026-09-17 17:18 - Updated: 2026-09-17 17:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: crash_dump: release keyring reference at the correct time restore_dm_crypt_keys_to_thread_keyring() gets a reference to the user keyring before restoring the saved dm-crypt keys. The same keyring reference is then passed to add_key_to_keyring() for each saved key, but add_key_to_keyring() drops that reference on every call. This is only balanced when exactly one key is restored. With multiple keys, the keyring reference is dropped too many times and may trigger a refcount underflow or use-after-free. When more than five keys are restored, a refcount underflow/use-after-free warning can be triggered. The early error paths after lookup_user_key() also return without dropping the keyring reference. Keep ownership of the keyring reference in restore_dm_crypt_keys_to_thread_keyring(), drop it once on all exit paths, and make add_key_to_keyring() only use the reference without consuming it.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ada2e5a44e99113e08ad9b7b71396c6c572204da
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b0f7343a002f9c8b8378011f60482c76f3216dfd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed566979f99c5516cad45a76ae25e2a4928ffb67
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/crash_dump_dm_crypt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b0f7343a002f9c8b8378011f60482c76f3216dfd",
              "status": "affected",
              "version": "62f17d9df6924cf805de5ae970470615c1c8d9f2",
              "versionType": "git"
            },
            {
              "lessThan": "ed566979f99c5516cad45a76ae25e2a4928ffb67",
              "status": "affected",
              "version": "62f17d9df6924cf805de5ae970470615c1c8d9f2",
              "versionType": "git"
            },
            {
              "lessThan": "ada2e5a44e99113e08ad9b7b71396c6c572204da",
              "status": "affected",
              "version": "62f17d9df6924cf805de5ae970470615c1c8d9f2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/crash_dump_dm_crypt.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-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\ncrash_dump: release keyring reference at the correct time\n\nrestore_dm_crypt_keys_to_thread_keyring() gets a reference to the user\nkeyring before restoring the saved dm-crypt keys.\n\nThe same keyring reference is then passed to add_key_to_keyring() for each\nsaved key, but add_key_to_keyring() drops that reference on every call.\nThis is only balanced when exactly one key is restored. With multiple\nkeys, the keyring reference is dropped too many times and may trigger a\nrefcount underflow or use-after-free.\n\nWhen more than five keys are restored, a refcount underflow/use-after-free\nwarning can be triggered.\n\nThe early error paths after lookup_user_key() also return without dropping\nthe keyring reference.\n\nKeep ownership of the keyring reference in\nrestore_dm_crypt_keys_to_thread_keyring(), drop it once on all exit paths,\nand make add_key_to_keyring() only use the reference without consuming it."
    }
  ],
  "id": "CVE-2026-93106",
  "lastModified": "2026-09-17T17:18:04.953",
  "metrics": {},
  "published": "2026-09-17T17:18:04.953",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ada2e5a44e99113e08ad9b7b71396c6c572204da"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b0f7343a002f9c8b8378011f60482c76f3216dfd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ed566979f99c5516cad45a76ae25e2a4928ffb67"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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