FKIE_CVE-2026-74671

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-22 16:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ima: fix out-of-bounds read in xattr_verify() The digest-length check in xattr_verify() mixes int and size_t: if (xattr_len - sizeof(xattr_value->type) - hash_start >= iint->ima_hash->length) sizeof() yields size_t, so the usual arithmetic conversions promote the whole left-hand side to unsigned 64-bit before the subtraction runs. For a truncated xattr this underflows instead of going negative: a 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1) turns "1 - 1 - 1" into SIZE_MAX, which is trivially >= ima_hash->length. The check then passes and the following memcmp() reads iint->ima_hash->length bytes starting past the end of the buffer vfs_getxattr_alloc() allocated for it. Nothing upstream clamps xattr_len back into a safe range first: ima_get_hash_algo() only special-cases xattr_len < 2 to pick a default algorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than failing when no HMAC key is loaded, so a truncated security.ima value reaches the length check as-is. Rewrite the comparison so every operand stays a signed int and no implicit conversion to size_t can occur.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/27f3924061592d0ef6b04e16f48754b6cb6adf27
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5ff232d31106f45ac87c3b64e1d35a0667777797
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7e515b6c9aab452a4f0734bd7208e4e780e164ca
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a784b4732ac7e51862b9b210c2d8b2ab9e83568c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b6cb134707a2127d90a58d69dd818679cae8033c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/caeb105c15ea2431fa8da7ecfa242d0c68272426
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d823b5f4557083d1dd92096f796a78a2b1b06d10
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dd04114af0d451091f7b8cbd26d9e37d011e9131
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "security/integrity/ima/ima_appraise.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d823b5f4557083d1dd92096f796a78a2b1b06d10",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "caeb105c15ea2431fa8da7ecfa242d0c68272426",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "a784b4732ac7e51862b9b210c2d8b2ab9e83568c",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "b6cb134707a2127d90a58d69dd818679cae8033c",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "7e515b6c9aab452a4f0734bd7208e4e780e164ca",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "27f3924061592d0ef6b04e16f48754b6cb6adf27",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "dd04114af0d451091f7b8cbd26d9e37d011e9131",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            },
            {
              "lessThan": "5ff232d31106f45ac87c3b64e1d35a0667777797",
              "status": "affected",
              "version": "3ea7a56067e663278470c04fd655adf809e72d4d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "security/integrity/ima/ima_appraise.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.13"
            },
            {
              "lessThan": "3.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nima: fix out-of-bounds read in xattr_verify()\n\nThe digest-length check in xattr_verify() mixes int and size_t:\n\n\tif (xattr_len - sizeof(xattr_value-\u003etype) - hash_start \u003e=\n\t\t\tiint-\u003eima_hash-\u003elength)\n\nsizeof() yields size_t, so the usual arithmetic conversions promote\nthe whole left-hand side to unsigned 64-bit before the subtraction\nruns. For a truncated xattr this underflows instead of going negative:\na 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1)\nturns \"1 - 1 - 1\" into SIZE_MAX, which is trivially \u003e= ima_hash-\u003elength.\nThe check then passes and the following memcmp() reads\niint-\u003eima_hash-\u003elength bytes starting past the end of the buffer\nvfs_getxattr_alloc() allocated for it.\n\nNothing upstream clamps xattr_len back into a safe range first:\nima_get_hash_algo() only special-cases xattr_len \u003c 2 to pick a default\nalgorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than\nfailing when no HMAC key is loaded, so a truncated security.ima value\nreaches the length check as-is.\n\nRewrite the comparison so every operand stays a signed int and no\nimplicit conversion to size_t can occur."
    }
  ],
  "id": "CVE-2026-74671",
  "lastModified": "2026-08-22T16:16:41.063",
  "metrics": {},
  "published": "2026-08-22T16:16:41.063",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/27f3924061592d0ef6b04e16f48754b6cb6adf27"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5ff232d31106f45ac87c3b64e1d35a0667777797"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7e515b6c9aab452a4f0734bd7208e4e780e164ca"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a784b4732ac7e51862b9b210c2d8b2ab9e83568c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b6cb134707a2127d90a58d69dd818679cae8033c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/caeb105c15ea2431fa8da7ecfa242d0c68272426"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d823b5f4557083d1dd92096f796a78a2b1b06d10"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dd04114af0d451091f7b8cbd26d9e37d011e9131"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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