CVE-2026-59200

Pillow is a Python imaging library. From 5.1.0 until 12.3.0, PdfParser.PdfStream.decode() in PIL/PdfParser.py calls zlib.decompress() with bufsize set to the PDF stream Length field without bounding the decompressed output size, allowing a crafted FlateDecode PDF stream to exhaust memory from a small file. This issue is fixed in version 12.3.0.

Score

CVSS 3.1 7.5 High

Status

Analyzed - security-advisories@github.com

Published

2026-07-14

Last modified

2026-10-24

Weaknesses

CWE-400, CWE-770

Affected products

• Pillow (Python)
• Pillow (Python-pillow)

References

• https://github.com/python-pillow/Pillow/security/advisories/GHSA-jjj6-mw9f-p565
• https://github.com/python-pillow/Pillow/pull/9718
• https://github.com/python-pillow/Pillow/commit/f7a31ea75e460e108c37126da1f47812f21f6b09
• https://github.com/python-pillow/Pillow/releases/tag/12.3.0