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CVE-2026-107287

Pydantic AI: Excessive resource use when local web fetching converts nested HTML PUBLISHED

Description (CNA)

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.7 and 2.52.0, the local web_fetch_tool and the WebFetch local fallback can consume excessive CPU and memory during HTML-to-Markdown conversion of attacker-controlled HTML containing deeply nested block elements. Conversion repeatedly reprocesses accumulated text and can greatly expand intermediate output before the returned-content limit is applied, allowing a model-directed fetch to delay other work in the process. Provider-native web fetching is not affected. This issue is fixed in versions 1.107.7 and 2.52.0.

Affected (CNA)

Vendor / productVersions
pydantic / pydantic-aiaffected >= 1.77.0, < 1.107.7; affected >= 2.0.0b1, < 2.52.0
pydantic / pydantic-ai-slimaffected >= 1.77.0, < 1.107.7; affected >= 2.0.0b1, < 2.52.0

CWE

CWE-400, CWE-407

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.