GitHub Advisoryadvisory · PyPI
GHSA-whj4-6x5x-4v2j FITS GZIP decompression bomb in Pillow
HIGH
Official page ↗
- Aliases
- CVE-2026-40192
- Ecosystem
- PyPI
- Packages
- pillow
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-400, CWE-770
- Reviewed
- 2026-04-13
Affected packages
• PyPI pillow: >= 10.3.0, < 12.2.0 → fixed in 12.2.0
Description
Impact
Pillow did not limit the amount of GZIP-compressed data read when decoding a FITS image, making it vulnerable to decompression bomb attacks. A specially crafted FITS file could cause unbounded memory consumption, leading to denial of service (OOM crash or severe performance degradation).
Patches
The amount of data read is now limited to the necessary amount.
Fixed in Pillow 12.2.0 (PR #9521).
Workarounds
Avoid Pillow >= 10.3.0, < 12.2.0
Only open specific image formats, excluding FITS.
Related
Alias · CVE (1)
- CVE-2026-40192 Pillow is a Python imaging library. vulnerability
References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-whj4-6x5x-4v2j web
- https://nvd.nist.gov/vuln/detail/CVE-2026-40192 advisory
- https://github.com/python-pillow/Pillow/pull/9521 web
- https://github.com/python-pillow/Pillow/commit/3cb854e8b2bab43f40e342e665f9340d861aa628 web
- https://github.com/python-pillow/Pillow package
- https://pillow.readthedocs.io/en/stable/releasenotes/12.2.0.html#prevent-fits-decompression-bomb web