high7.1
CVE-2026-96642
Pillow: TarIO negative size field causes infinite CPU-spin loop
Impact
Pillow is a Python imaging library. Prior to 13.0.0, the TarIO initializer in src/PIL/TarIO.py accepts a negative octal member size and computes a backward seek that returns to the same 512-byte header. When the requested member name does not match, the parser repeatedly reads that header, consumes a full CPU core, and never returns. TarIO is reached only when an application directly uses PIL.TarIO.TarIO rather than the default Image.open() path. This issue is fixed in version 13.0.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | Pillow | < 13.0.0 | 13.0.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Python | Pillow | before 13.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-3j72-p6qg-6xp7
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-3j72-p6qg-6xp7
- https://nvd.nist.gov/vuln/detail/CVE-2026-96642
- https://github.com/python-pillow/Pillow/pull/10012
- https://github.com/python-pillow/Pillow/commit/19b695fdcc5eddc37374e2b1645fc4185edaf71d
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0