Pillow vulnerability can cause write buffer overflow on BCn encoding (CVE-2025-48379)

Pillow vulnerability can cause write buffer overflow on BCn encoding (CVE-2025-48379) | HOL Guard CVE

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps pillow (pypi), pillow (pypi). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
pillowpypi	>=0 <89f1f4626a2aaf5f3d5ca6437f41def2998fbe09 <ef98b3510e3e4f14b547762764813d7e5ca3c5a4	89f1f4626a2aaf5f3d5ca6437f41def2998fbe09, ef98b3510e3e4f14b547762764813d7e5ca3c5a4
pillowpypi	>=11.2.0 <11.3.0	11.3.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for pillow, pillow.
Review the reported fix. Update pillow to 89f1f4626a2aaf5f3d5ca6437f41def2998fbe09; pillow to 11.3.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 1, 2025
Evidence: source:osv:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Aug 7, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.