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BREW-AIDER-CVE-2026-42311 (GHSA-PWV6-VV43-88GR)

Vulnerability from osv_homebrew – Published: 2026-08-13 16:35 – Updated: 2026-09-09 23:40 – Source website
VLAI
Summary
Pillow has an OOB Write with Invalid PSD Tile Extents (Integer Overflow)
Details

Impact

Processing a malicious PSD file could lead to memory corruption, potentially resulting in a crash or arbitrary code execution.

Patches

Patched version: 12.2.0

Pillow 12.1.1 addressed CVE-2026-25990 by adding checks for tile extents in PSD image decoding/encoding to prevent an out-of-bounds write. However, the bounds checks computed tile extent sums using types susceptible to integer overflow, meaning a PSD image with carefully chosen tile dimensions could produce values that wrap around and bypass the checks, still triggering an out-of-bounds write in src/decode.c and src/encode.c. The fix avoids adding extents together before comparison.

Workarounds

Use any version but affected versions: >= 10.3.0, < 12.2.0

Resources

  • Fix: https://github.com/python-pillow/Pillow/pull/9520
  • Original issue: CVE-2026-25990 (Pillow 12.1.1)
Severity
8.6 (High)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "pillow",
        "resource_purl": "pkg:pypi/pillow@12.1.1",
        "upstream_fixed_in": "12.2.0"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "aider",
        "purl": "pkg:brew/aider"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/pillow@12.1.1",
        "name": "pillow",
        "resource": "pillow",
        "strategy": "registry",
        "subject_version": "12.1.1"
      }
    ]
  },
  "details": "### Impact\nProcessing a malicious PSD file could lead to memory corruption, potentially resulting in a crash or arbitrary code execution.\n\n### Patches\nPatched version: 12.2.0\n\nPillow 12.1.1 addressed CVE-2026-25990 by adding checks for tile extents in PSD image decoding/encoding to prevent an out-of-bounds write. However, the bounds checks computed tile extent sums using types susceptible to integer overflow, meaning a PSD image with carefully chosen tile dimensions could produce values that wrap around and bypass the checks, still triggering an out-of-bounds write in src/decode.c and src/encode.c. The fix avoids adding extents together before comparison.\n\n### Workarounds\nUse any version but affected versions: \u003e= 10.3.0, \u003c 12.2.0\n\n### Resources\n - Fix: https://github.com/python-pillow/Pillow/pull/9520 \n - Original issue: CVE-2026-25990 (Pillow 12.1.1)",
  "id": "BREW-aider-CVE-2026-42311",
  "modified": "2026-09-09T23:40:56Z",
  "published": "2026-08-13T16:35:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-cfh3-3jmp-rvhc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-pwv6-vv43-88gr"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42311"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/pull/9520"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/commit/58f9a1d166dcb0c274807d4423522d205b0c35ea"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/python-pillow/Pillow"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/12.2.0"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Pillow has an OOB Write with Invalid PSD Tile Extents (Integer Overflow)",
  "upstream": [
    "GHSA-pwv6-vv43-88gr",
    "BIT-pillow-2026-42311",
    "CVE-2026-42311",
    "PYSEC-2026-2252"
  ]
}



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