← CVE Intelligence

CVE-2026-107290

Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch` PUBLISHED

Description (CNA)

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.6 and 2.44.0, the local web_fetch_tool and the WebFetch local fallback process server-controlled responses with quadratic title extraction, whitespace normalization, and ordered-list numbering. An attacker-controlled page of modest size can therefore block the event loop for an extended period, stalling other agent runs and requests, while unsupported codecs or excessive HTML or JSON nesting can abort an individual run. This issue is fixed in versions 1.107.6 and 2.44.0.

Affected (CNA)

Vendor / productVersions
pydantic / pydantic-aiaffected >= 1.77.0, < 1.107.6; affected >= 2.0.0b1, < 2.44.0
pydantic / pydantic-ai-slimaffected >= 1.77.0, < 1.107.6; affected >= 2.0.0b1, < 2.44.0

CWE

CWE-1333

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.