CVE-2026-96641Pillow: Reachable undefined behavior in native integer operations, potentially leading to denial of service or logic integrity compromise
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-190
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 21, 2026
- First seen by InfoSec Signals
- Oct 21, 2026
Affected products
python-pillow Pillow python_pillow:pillow (from the name) | before 13.0.0 | CNA record |
References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-4rm8-3hmm-39fgx-refsource-confirm
- https://github.com/python-pillow/Pillow/pull/10010x-refsource-misc
- https://github.com/python-pillow/Pillow/commit/80de4be9e38d3a6148dd4d8491eb80cd12b760a4x-refsource-misc
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.