CVE-2026-42308 Pillow: Integer overflow when processing fonts

What is CVE-2026-42308?

CVE-2026-42308 is a medium-severity vulnerability in Python Pillow, published on 9 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Pillow is a Python imaging library. Prior to version 12.2.0, if a font advances for each glyph by an exceeding large amount, when Pillow keeps track of the current position, it may lead to an integer overflow. This issue has been patched in version 12.2.0.

Weakness: CWE-190

Which versions are affected by CVE-2026-42308?

4 open source packages ship an affected version, including pillow. It affects 1 product.

Products include Python Pillow.

How do I fix CVE-2026-42308?

Upgrade pillow to 12.2.0 or later.

Is CVE-2026-42308 being exploited?

There is no known exploitation of CVE-2026-42308 in the wild and no public exploit code.

Other vulnerabilities in Python Pillow

• CVE-2014-3007 Pillow command injection Critical 10.0
• CVE-2026-96639 Pillow multi-frame loaders can reuse stale native image storage after mode transitions Critical 9.8
• CVE-2022-30595 Buffer over-flow in Pillow Critical 9.8
• CVE-2021-25289 Out of bounds write in Pillow Critical 9.8
• CVE-2016-4009 Pillow Integer overflow in ImagingResampleHorizontal Critical 9.8

All Python Pillow vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-pillow-2026-42308, CLEANSTART-2026-GE72398, CLEANSTART-2026-YZ67479, DEBIAN-CVE-2026-42308, ECHO-784c-565e-18bc, GHSA-wjx4-4jcj-g98j and 9 more.