Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-107292
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-08 17:17:14 UTC
Updated2026-10-08 17:17:14 UTC
DescriptionPydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 2.30.0, the Agent.to_web() and clai web development chat server does not validate the Host header, allowing a website visited by a developer to use DNS rebinding to reach a loopback-hosted agent as a same-origin service. The hostile page can read the served UI and submit chat requests that execute agent tools with the local process's privileges and credentials, causing data disclosure or unwanted side effects. Binding to localhost, Origin checks, and CSRF tokens do not prevent the same-origin DNS rebinding path. This issue is fixed in versions 1.107.5 and 2.30.0.

Risk And Classification

Primary CVSS: v3.1 6.4 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L

Problem Types: CWE-346 | CWE-350 | CWE-346 CWE-346: Origin Validation Error | CWE-350 CWE-350: Reliance on Reverse DNS Resolution for a Security-Critical Action

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L
3.1CNADECLARED6.4MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Pydantic Pydantic-ai affected >= 1.34.0, < 2.0.0b1 Not specified
CNA Pydantic Pydantic-ai affected >= 2.0.0b1, < 2.30.0 Not specified
CNA Pydantic Pydantic-ai-slim affected >= 1.34.0, < 2.0.0b1 Not specified
CNA Pydantic Pydantic-ai-slim affected >= 2.0.0b1, < 2.30.0 Not specified

References

ReferenceSourceLinkTags
github.com/pydantic/pydantic-ai/security/advisories/GHSA-q2xc-rrxj-58x9 [email protected] github.com
github.com/pydantic/pydantic-ai/commit/394cc1d31656620704a703a2daed752af... [email protected] github.com
github.com/pydantic/pydantic-ai/pull/7438 [email protected] github.com
github.com/pydantic/pydantic-ai/pull/7437 [email protected] github.com
github.com/pydantic/pydantic-ai/releases/tag/v2.30.0 [email protected] github.com
github.com/pydantic/pydantic-ai/commit/871c7aeec5dfed2138655ccbccbf15c6d... [email protected] github.com
github.com/pydantic/pydantic-ai/releases/tag/v1.107.5 [email protected] github.com
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