CVE-2026-96637: python pillow

CVSS 7.1 (high) · published 2026-10-21

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.

Affected products (NVD): python pillow

Fixed in (NVD): 13.0.0

Weakness: CWE-400, CWE-409

Source: NVD CVE-2026-96637

References

• https://github.com/python-pillow/Pillow/commit/7cb0e02389d8aac2a60896a490f572db0b07b841
• https://github.com/python-pillow/Pillow/pull/10076
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-g842-9rc4-69pw

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