PYSEC-2026-4338

Vulnerability from pysec - Published: 2026-10-21 21:20 - Updated: 2026-10-28 10:34
VLAI
Details

Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Impacted products
Name purl
pillow pkg:pypi/pillow
Aliases
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "pillow",
        "purl": "pkg:pypi/pillow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "13.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0",
        "1.1",
        "1.2",
        "1.3",
        "1.4",
        "1.5",
        "1.6",
        "1.7.0",
        "1.7.1",
        "1.7.2",
        "1.7.3",
        "1.7.4",
        "1.7.5",
        "1.7.6",
        "1.7.7",
        "1.7.8",
        "10.0.0",
        "10.0.1",
        "10.1.0",
        "10.2.0",
        "10.3.0",
        "10.4.0",
        "11.0.0",
        "11.1.0",
        "11.2.1",
        "11.3.0",
        "12.0.0",
        "12.1.0",
        "12.1.1",
        "12.2.0",
        "12.3.0",
        "2.0.0",
        "2.1.0",
        "2.2.0",
        "2.2.1",
        "2.2.2",
        "2.3.0",
        "2.3.1",
        "2.3.2",
        "2.4.0",
        "2.5.0",
        "2.5.1",
        "2.5.2",
        "2.5.3",
        "2.6.0",
        "2.6.1",
        "2.6.2",
        "2.7.0",
        "2.8.0",
        "2.8.1",
        "2.8.2",
        "2.9.0",
        "3.0.0",
        "3.1.0",
        "3.1.0.rc1",
        "3.1.0rc1",
        "3.1.1",
        "3.1.2",
        "3.2.0",
        "3.3.0",
        "3.3.1",
        "3.3.2",
        "3.3.3",
        "3.4.0",
        "3.4.1",
        "3.4.2",
        "4.0.0",
        "4.1.0",
        "4.1.1",
        "4.2.0",
        "4.2.1",
        "4.3.0",
        "5.0.0",
        "5.1.0",
        "5.2.0",
        "5.3.0",
        "5.4.0",
        "5.4.0.dev0",
        "5.4.1",
        "6.0.0",
        "6.1.0",
        "6.2.0",
        "6.2.1",
        "6.2.2",
        "7.0.0",
        "7.1.0",
        "7.1.1",
        "7.1.2",
        "7.2.0",
        "8.0.0",
        "8.0.1",
        "8.1.0",
        "8.1.1",
        "8.1.2",
        "8.2.0",
        "8.3.0",
        "8.3.1",
        "8.3.2",
        "8.4.0",
        "9.0.0",
        "9.0.1",
        "9.1.0",
        "9.1.1",
        "9.2.0",
        "9.3.0",
        "9.4.0",
        "9.5.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-96637",
    "GHSA-g842-9rc4-69pw"
  ],
  "details": "Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.",
  "id": "PYSEC-2026-4338",
  "modified": "2026-10-28T10:34:04.689455Z",
  "published": "2026-10-21T21:20:31.927Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-g842-9rc4-69pw"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/python-pillow/Pillow/pull/10076"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python-pillow/Pillow/commit/7cb0e02389d8aac2a60896a490f572db0b07b841"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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