Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Pillow versions before 12.3.0 have a flaw in the BDF font loader (BdfFontFile). Glyph dimensions read from a BDF file are passed to Image.new() without the decompression bomb check, so Pillow's usual pixel limit is skipped. An attacker who can supply a BDF font file, for example through ImageFont.load() on untrusted input, can force large memory allocations, which can cause a denial of service. Upgrade to Pillow 12.3.0 or later. The source gives no other workaround.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0052, the 44th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 3 Jul 2026, 08:33 UTC Published by the maintainers as a GitHub repository advisory
- 31 Oct 2026, 14:29 UTC First seen by agentprime
- 31 Oct 2026, 14:29 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-45hq-cxwh-f6vc
- OSV: GHSA-45hq-cxwh-f6vc
- github.com/python-pillow/Pillow/security/advisories/GHSA-45hq-cxwh-f6vc
- nvd.nist.gov/vuln/detail/CVE-2026-55379
- github.com/python-pillow/Pillow/commit/0a263e6264aa5399988d9acd3bbfbca2ca3ec77d
- github.com/pypa/advisory-database/tree/main/vulns/pillow/PYSEC-2026-2255.yaml
- github.com/python-pillow/Pillow
- github.com/python-pillow/Pillow/blob/main/docs/releasenotes/12.3.0.rst