CVE-2026-90203

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: Squashfs: check block offset is not negative If a negative offset is read off disk (for example the offset into the decompressed fragment block), this will cause squashfs_copy_data() to perform an out of bounds access. Fix by checking if offset is negative, and returning 0. This matches existing behaviour where an offset beyond the block returns 0 bytes copied. To trigger this out of bounds access requires a crafted Squashfs filesystem and CAP_SYS_ADMIN to mount it. Unprivileged users will not be able to mount such a filesystem, but once mounted, an unprivileged user can trigger the out of bounds access by reading the crafted file with the negative offset.

Severity

HIGH

CVSS score

7.1 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-17 17:17:15.320000

Last modified

2026-10-19 09:19:10.377000

View original CVE JSON

{
  "id": "CVE-2026-90203",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:17:15.320",
  "lastModified": "2026-10-19T09:19:10.377",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSquashfs: check block offset is not negative\n\nIf a negative offset is read off disk (for example the offset into the\ndecompressed fragment block), this will cause squashfs_copy_data() to\nperform an out of bounds access.\n\nFix by checking if offset is negative, and returning 0.  This matches\nexisting behaviour where an offset beyond the block returns 0 bytes\ncopied.\n\nTo trigger this out of bounds access requires a crafted Squashfs\nfilesystem and CAP_SYS_ADMIN to mount it.  Unprivileged users will not be\nable to mount such a filesystem, but once mounted, an unprivileged user\ncan trigger the out of bounds access by reading the crafted file with the\nnegative offset."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/squashfs/cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "b169185d5c672b989985c6c2e38cafab2548ba88",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "c2a126fca820ae74872da28de68dc74d4595dc4b",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "95dadf366c117dcdca78a570e6832071deab1ecd",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "3d2f0cb66c909ea2312cdef465165bb9a3ba2d84",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "bbb2218eb072b0a15dc063929200183bd23c2344",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "d0a3729d464fcf516416a41cf304c0c92126ee03",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f400e12656ab518be107febfe2315fb1eab5a342",
              "lessThan": "e300eb5002925b29be803d2661af07266cfa267e",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/squashfs/cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2.6.29",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "2.6.29",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.270",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.221",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.188",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.157",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.110",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "REQUIRED",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.2
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/3d2f0cb66c909ea2312cdef465165bb9a3ba2d84",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/95dadf366c117dcdca78a570e6832071deab1ecd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b169185d5c672b989985c6c2e38cafab2548ba88",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bbb2218eb072b0a15dc063929200183bd23c2344",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c2a126fca820ae74872da28de68dc74d4595dc4b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d0a3729d464fcf516416a41cf304c0c92126ee03",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e300eb5002925b29be803d2661af07266cfa267e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}