Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Python | Pillow | < 13.0.0 |
Related Weaknesses (CWE)
References
- https://github.com/python-pillow/Pillow/commit/80de4be9e38d3a6148dd4d8491eb80cd1Patch
- https://github.com/python-pillow/Pillow/pull/10010Issue Tracking
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0Release Notes
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-4rm8-3hmm-39fgVendor Advisory
FAQ
What is CVE-2026-96641?
CVE-2026-96641 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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_M...
How severe is CVE-2026-96641?
CVE-2026-96641 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-96641?
Check the references section above for vendor advisories and patch information. Affected products include: Python Pillow.