PYSEC-2026-2874
Pillow has a PDF Parsing Trailer Infinite Loop (DoS)
Quick fix
PYSEC-2026-2874 — pillow: upgrade to the fixed version with the command below.
pip install --upgrade 'pillow>=12.2.0'Details
### Impact An attacker can supply a malicious PDF that causes the process to hang indefinitely, consuming 100% CPU and making the application unresponsive.
### Patches Patched version: 12.2.0.
PdfParser (introduced in Pillow 4.2.0) follows Prev pointers in PDF trailers to read cross-reference sections. If a trailer's Prev pointer references an offset that has already been processed — either pointing to itself or forming a longer cycle — the parser enters an infinite loop. Pillow now tracks previously processed trailer offsets and raises an error if a cycle is detected.
### Workarounds Use any version but the affected versions: >= 4.2.0, < 12.2.0
### Resources - Fix: https://github.com/python-pillow/Pillow/pull/9519
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-r73j-pqj5-w3x7[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-42310[ADVISORY]
- https://github.com/python-pillow/Pillow/pull/9519[WEB]
- https://github.com/python-pillow/Pillow/commit/3bf614e4b8615d0ce1d5039efaf6db447fe7c468[WEB]
- https://github.com/python-pillow/Pillow[PACKAGE]
- https://github.com/python-pillow/Pillow/releases/tag/12.2.0[WEB]
- https://pypi.org/project/pillow[PACKAGE]
- https://github.com/advisories/GHSA-r73j-pqj5-w3x7[ADVISORY]