Pillow vulnerability can cause write buffer overflow on BCn encoding
There is a heap buffer overflow when writing a sufficiently large (>64k encoded with default settings) image in the DDS format due to writing into a buffer without checking for available space.
This only affects users who save untrusted data as a compressed DDS image.
- Unclear how large the potential write could be. It is likely limited by process segfault, so it's not necessarily deterministic. It may be practically unbounded.
- Unclear if there's a restriction on the bytes that could be emitted. It's likely that the only restriction is that the bytes would be emitted in chunks of 8 or 16.
This was introduced in Pillow 11.2.0 when the feature was added.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pillow | >= 11.2.0, < 11.3.0 | 11.3.0 |
References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-xg8h-j46f-w952
- https://github.com/python-pillow/Pillow/commit/ef98b3510e3e4f14b547762764813d7e5ca3c5a4
- https://github.com/python-pillow/Pillow/pull/9041
- https://github.com/python-pillow/Pillow/releases/tag/11.3.0
- https://nvd.nist.gov/vuln/detail/CVE-2025-48379
- https://github.com/pypa/advisory-database/tree/main/vulns/pillow/PYSEC-2025-61.yaml
- https://github.com/python-pillow/Pillow
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H- Weakness (CWE)
CWE-122- Platform
- Python (PyPI)
- Package
pillow- Disclosed
- 01.07.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2025-61 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-xg8h-j46f-w952 - 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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Pillow vulnerability can cause write buffer overflow on BCn encoding this entry
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