CVE-2026-55379 Pillow `BdfFontFile`: `Image.new()` called without `_decompression_bomb_check()` — bomb protection bypass via font loading

What is CVE-2026-55379?

CVE-2026-55379 is a high-severity denial of service vulnerability in Python Pillow, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Pillow is a Python imaging library. Prior to 12.3.0, PIL/BdfFontFile.py bdf_char() read the BBX width and height field from a BDF font file and passed attacker-controlled dimensions to Image.new() without calling Image._decompression_bomb_check(), bypassing Pillow's documented decompression bomb protection and allowing excessive memory allocation. This issue is fixed in version 12.3.0.

Weakness: CWE-789

Which versions are affected by CVE-2026-55379?

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

Products include Python Pillow.

How do I fix CVE-2026-55379?

Upgrade pillow to 12.3.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-55379 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55379 exists.

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-2026-55379, DEBIAN-CVE-2026-55379, ECHO-f7cd-a473-7e12, GHSA-45hq-cxwh-f6vc, MINI-43g3-m8hg-xcfj, MINI-4vqv-3q85-gg66 and 12 more.