Inefficient Algorithmic Complexity Affecting pillow package, versions [5.4.0,13.0.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-PILLOW-21277778
- published20 Oct 2026
- disclosed19 Oct 2026
- creditUnknown
Introduced: 19 Oct 2026
NewCVE-2026-112401 (opens in a new tab)How to fix?
Upgrade pillow to version 13.0.0 or higher.
Overview
Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity via repeated string concatenation in the _seek function of src/PIL/GifImagePlugin.py when parsing GIF comment extension blocks. Each comment block encountered during frame seeking is appended to a growing byte string using +=, causing quadratic memory and CPU usage when a GIF file contains a large number of comment blocks. An attacker can supply a GIF file with many comment extension blocks to trigger excessive resource consumption and crash the process.