Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.107.6, 2.44.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- pydantic pydantic-ai
From 1.77.0 · fixed in 1.107.6; From 2.0.0b1 · fixed in 2.44.0
- pydantic pydantic-ai-slim
From 1.77.0 · fixed in 1.107.6; From 2.0.0b1 · fixed in 2.44.0
- pydantic-aiPyPI
From 1.77.0 · fixed in 1.107.6
- pydantic-aiPyPI
From 2.0.0b1 · fixed in 2.44.0
- pydantic-ai-slimPyPI
From 1.77.0 · fixed in 1.107.6
- pydantic-ai-slimPyPI
From 2.0.0b1 · fixed in 2.44.0
- pydantic-aiPyPI
From 1.77.0 · fixed in 1.107.6; From 2.0.0b1 · fixed in 2.44.0
- pydantic-ai-slimPyPI
From 1.77.0 · fixed in 1.107.6; From 2.0.0b1 · fixed in 2.44.0