FITS GZIP decompression bomb in Pillow
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.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pillow | >= 10.3.0, < 12.2.0 | 12.2.0 |
References
- https://access.redhat.com/security/cve/CVE-2026-40192
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40192.json
- https://access.redhat.com/errata/RHSA-2026:16008
- https://access.redhat.com/errata/RHSA-2026:16009
- https://access.redhat.com/errata/RHSA-2026:16030
- https://access.redhat.com/errata/RHSA-2026:16174
- https://access.redhat.com/errata/RHSA-2026:17609
- https://access.redhat.com/errata/RHSA-2026:17611
- https://access.redhat.com/errata/RHSA-2026:19375
- https://access.redhat.com/errata/RHSA-2026:19712
- https://access.redhat.com/errata/RHSA-2026:21017
- https://access.redhat.com/errata/RHSA-2026:22465
- https://access.redhat.com/errata/RHSA-2026:22629
- https://access.redhat.com/errata/RHSA-2026:22840
- https://access.redhat.com/errata/RHSA-2026:23361
- https://access.redhat.com/errata/RHSA-2026:24761
- https://access.redhat.com/errata/RHSA-2026:24762
- https://access.redhat.com/errata/RHSA-2026:24853
- https://access.redhat.com/errata/RHSA-2026:24866
- https://access.redhat.com/errata/RHSA-2026:24977
- https://access.redhat.com/errata/RHSA-2026:27076
- https://access.redhat.com/errata/RHSA-2026:34365
- https://access.redhat.com/errata/RHSA-2026:34366
- https://access.redhat.com/errata/RHSA-2026:34368
- https://access.redhat.com/errata/RHSA-2026:37275
- https://pillow.readthedocs.io/en/stable/releasenotes/12.2.0.html#prevent-fits-decompression-bomb
- https://bugzilla.redhat.com/show_bug.cgi?id=2458856
- https://github.com/python-pillow/Pillow/commit/3cb854e8b2bab43f40e342e665f9340d861aa628
- https://github.com/python-pillow/Pillow/pull/9521
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-whj4-6x5x-4v2j
- https://nvd.nist.gov/vuln/detail/CVE-2026-40192
- https://github.com/python-pillow/Pillow
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-400, CWE-770- Platform
- Python (PyPI)
- Package
pillow- Disclosed
- 13.04.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2250 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-whj4-6x5x-4v2j - CC BY 4.0
Vulnerability history: pillow
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 81
- First → latest
- 04.2014 10.2026
- Without a fix
- 0
- Exploited in attacks
- 1
Severity breakdown
- Critical 10
- High 53
- Medium 16
- Low 1
- Unrated 1
Disclosures per year
- 2017: 1
- 2018: 0
- 2019: 1
- 2020: 10
- 2021: 20
- 2022: 8
- 2023: 3
- 2024: 2
- 2025: 1
- 2026: 23
earlier: 12
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FITS GZIP decompression bomb in Pillow this entry
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