CVE-2026-107290
Published:October 08, 2026
Updated:October 10, 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.
Affected Packages
https://github.com/pydantic/pydantic-ai.git (GITHUB):
Affected version(s) >=v1.77.0 <v1.107.6Fix Suggestion:
Update to version v1.107.6https://github.com/pydantic/pydantic-ai.git (GITHUB):
Affected version(s) >=v2.0.0b1 <v2.44.0Fix Suggestion:
Update to version v2.44.0pydantic-ai-slim (PYTHON):
Affected version(s) >=2.0.0b1 <2.44.0Fix Suggestion:
Update to version 2.44.0pydantic-ai (PYTHON):
Affected version(s) >=2.0.0b1 <2.44.0Fix Suggestion:
Update to version 2.44.0pydantic-ai (PYTHON):
Affected version(s) >=1.77.0 <1.107.6Fix Suggestion:
Update to version 1.107.6pydantic-ai-slim (PYTHON):
Affected version(s) >=1.77.0 <1.107.6Fix Suggestion:
Update to version 1.107.6Related Resources (17)
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Contact UsCVSS v4
Base Score:
7.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
EPSS
Base Score:
0.42