CVE-2026-96644: Pillow: Heap over-read in WMF/EMF rendering via 16-bit dimension truncation (Windows builds)
On Windows builds, Pillow stores EMF and WMF image dimensions without a range check and passes them to the native drawwmf handler. That code sizes its allocation from dimensions truncated into 16-bit header fields but copies the result using the full 32-bit dimensions. A crafted metafile that is wide and short passes the decompression-bomb pixel check yet causes a heap over-read.
References
- github.com/advisories/GHSA-9v9v-9qvf-h2hj
- github.com/python-pillow/Pillow/commit/4cf46bee338304c5c8968fd7f132ba0d40c428b7
- github.com/python-pillow/Pillow/pull/10120
- github.com/python-pillow/Pillow/releases/tag/13.0.0
- github.com/python-pillow/Pillow/security/advisories/GHSA-9v9v-9qvf-h2hj
- nvd.nist.gov/vuln/detail/CVE-2026-96644
Code Behaviors & Features
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