CVE-2026-112399
Pillow: APNG background disposal allocates full canvas before decompression bomb check
Reported by github_m · Published October 19, 2026
Pillow is a Python imaging library. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| py3-pytorch-cuda-13.0 | Chainguard | 2.14.1-r2 |
| open-webui | Chainguard | 0.12.3-r6 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| python-pillow | Pillow | >= 8.1.0, < 13.0.0 |
| chainguard | py3-pytorch-cuda-13.0 | 0 |
| chainguard | open-webui | 0 |
| python-pillow | Pillow | 8.1.0 |
| chainguard | superset-fips-6.1 | 0 |
| wolfi | py3-pillow | 0 |
| wolfi | open-webui | 0 |
| chainguard | py3-pillow | 0 |
| PyPI | Pillow | 8.1.0 |
| chainguard | apache-beam-python-3.12-sdk | 0 |
| chainguard | nemo-gym | 0 |
| chainguard | nemo-rl-cuda-13.0 | 0 |
| chainguard | openstack-horizon-2025.2 | 0 |
Timeline
- Oct 19, 2026 CVE Published
- Oct 20, 2026 EPSS Score (7 in total, the first dated here)
- Oct 20, 2026 Coalition ESS Score
- Oct 28, 2026 CVE Updated
- Oct 30, 2026 Security Advisory
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References
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 x_refsource_CONFIRM
- https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48 x_refsource_MISC
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0 x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-112399 advisory
- https://github.com/advisories/GHSA-5xm2-6676-qcp9 advisory