[ CVE-2026-96641 · Published 21 Oct 2026 ]
Pillow: Reachable undefined behavior in native integer operations, potentially leading to denial of service or logic integrity compromise
CVSS 6.5
EPSS <1%Fix available
[ Description ]Official description
Pillow is a Python imaging library. Prior to 13.0.0, PILfont text-width accumulation in src/_imaging.c checks positive glyph advances against INT_MAX but does not check negative advances against INT_MIN. Repeating a signed 16-bit advance of -32768 can therefore execute a signed C integer overflow in xsize += dx, producing a large positive width from a negative mathematical result. Applications that use getlength(), getsize(), or derived layout, quota, serialization, or allocation calculations can experience logic-integrity errors or resource consumption, while the high-level mask path commonly retains a decompression-bomb check. This issue is fixed in version 13.0.0.
[ Fixes ]Fixes and patches
- pillow 13.0.0Fixed version · GitHub Advisories · pip package pillow: upgrade to 13.0.0 or later (affected < 13.0.0)
[ Packages ]Affected open-source packages
- pillow pipAffected < 13.0.0 · fixed in 13.0.0 · GHSA-4rm8-3hmm-39fg