Inefficient Algorithmic Complexity Affecting pydantic-ai-slim package, versions [2.0.0b1,2.52.0)[1.77.0,1.107.7)
Threat Intelligence
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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- published13 Oct 2026
- disclosed8 Oct 2026
- creditSounLabs
Introduced: 8 Oct 2026
NewCVE-2026-107287 (opens in a new tab)How to fix?
Upgrade pydantic-ai-slim to version 2.52.0, 1.107.7 or higher.
Overview
pydantic-ai-slim is an Agent Framework / shim to use Pydantic with LLMs, slim package
Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity via the _convert_html function in web_fetch.py, where processing a deeply nested or adversarially structured HTML document causes unbounded HTML-to-Markdown conversion cost. An attacker who controls a web page fetched via the web_fetch tool can serve HTML with deeply nested elements (such as <dd> or list items) that cause the markdownify-based converter to produce enormous intermediate strings, holding the GIL for seconds and crashing the process.