Answer in brief
CVE-2026-107290 records a Medium severity (CVSS 6.5) vulnerability in Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`. The current sources do not mark it as known exploited. The current feed maps pydantic/pydantic-ai (generic), pydantic/pydantic-ai-slim (generic), pydantic-ai (pip), pydantic-ai (pip) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps pydantic/pydantic-ai (generic), pydantic/pydantic-ai-slim (generic), pydantic-ai (pip), pydantic-ai (pip) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| pydantic/pydantic-aigeneric | >=1.77.0 <1.107.6 || >=2.0.0b1 <2.44.0 | 1.107.6, 2.44.0 |
| pydantic/pydantic-ai-slimgeneric | >=1.77.0 <1.107.6 || >=2.0.0b1 <2.44.0 | 1.107.6, 2.44.0 |
| pydantic-aipip | >=1.77.0,<1.107.6 | 1.107.6 |
| pydantic-aipip | >=2.0.0b1,<2.44.0 | 2.44.0 |
| pydantic-ai-slimpip | >=1.77.0,<1.107.6 | 1.107.6 |
| pydantic-ai-slimpip | >=2.0.0b1,<2.44.0 | 2.44.0 |
| pydantic-aipypi | >=1.77.0 <1.107.6 | 1.107.6 |
| pydantic-aipypi | >=2.0.0b1 <2.44.0 | 2.44.0 |
| pydantic-ai-slimpypi | >=1.77.0 <1.107.6 | 1.107.6 |
| pydantic-ai-slimpypi | >=2.0.0b1 <2.44.0 | 2.44.0 |
Published upstream
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 8, 2026
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.
Quoted source text, attributed separately from HOL analysis.