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CVE-2026-74671 (GCVE-0-2026-74671)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-22 15:32
VLAI
Title
ima: fix out-of-bounds read in xattr_verify()
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < d823b5f4557083d1dd92096f796a78a2b1b06d10 (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < caeb105c15ea2431fa8da7ecfa242d0c68272426 (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < a784b4732ac7e51862b9b210c2d8b2ab9e83568c (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < b6cb134707a2127d90a58d69dd818679cae8033c (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < 7e515b6c9aab452a4f0734bd7208e4e780e164ca (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < 27f3924061592d0ef6b04e16f48754b6cb6adf27 (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < dd04114af0d451091f7b8cbd26d9e37d011e9131 (git)
Affected: 3ea7a56067e663278470c04fd655adf809e72d4d , < 5ff232d31106f45ac87c3b64e1d35a0667777797 (git)
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Linux Linux Affected: 3.13
Unaffected: 0 , < 3.13 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.152 , ≤ 6.6.* (semver)
Unaffected: 6.12.104 , ≤ 6.12.* (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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                  "versionStartIncluding": "3.13",
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      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-22T15:32:41.480Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/d823b5f4557083d1dd92096f796a78a2b1b06d10"
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          "url": "https://git.kernel.org/stable/c/caeb105c15ea2431fa8da7ecfa242d0c68272426"
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          "url": "https://git.kernel.org/stable/c/a784b4732ac7e51862b9b210c2d8b2ab9e83568c"
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        },
        {
          "url": "https://git.kernel.org/stable/c/5ff232d31106f45ac87c3b64e1d35a0667777797"
        }
      ],
      "title": "ima: fix out-of-bounds read in xattr_verify()",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74671",
    "datePublished": "2026-08-22T15:32:41.480Z",
    "dateReserved": "2026-08-15T05:44:03.925Z",
    "dateUpdated": "2026-08-22T15:32:41.480Z",
    "state": "PUBLISHED"
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    "epss": {
      "cve": "CVE-2026-74671",
      "date": "2026-09-15",
      "epss": "0.00177",
      "percentile": "0.07418"
    },
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      "title": "ima: fix out-of-bounds read in xattr_verify()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74671.json",
      "version": "3"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-24T11:54:24+00:00",
      "cve": "CVE-2026-74671",
      "id": "CVE-2026-74671",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ima: fix out-of-bounds read in xattr_verify()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74671.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:16:49Z",
      "cve": "CVE-2026-74671",
      "id": "CVE-2026-74671",
      "initial_release_date": "2026-08-28T16:38:58Z",
      "product_status:known_affected": "353",
      "product_status:known_not_affected": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74671",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74671.json",
      "version": "5"
    }
  }
}



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