CVE-2026-107292CWE-346CWE-350

CVE-2026-107292

Medium · published October 8, 2026

CVSS v3.1
6.4
EPSS
0%
Percentile
2.5
In the wild
Unconfirmed
What it is

Pydantic 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.

The record
Technical detail
CVSS v3.1
6.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L
CVSS v4.0
Not supplied
EPSS
0.00132 · 2.5th percentile
Weaknesses
CWE-346 · Origin Validation Error; CWE-350 · Reliance on Reverse DNS Resolution for a Security-Critical Action
Published
2026-10-08T21:17Z
Affected products (2)
ProductVersionsFixed in
pydantic/pydantic_ai≥ 1.34.0, < 1.107.51.107.5
pydantic/pydantic_ai≥ 2.0.0, < 2.30.02.30.0
References (7)
https://github.com/pydantic/pydantic-ai/commit/394cc1d31656620704a703a2daed752afa5135fe · [email protected]https://github.com/pydantic/pydantic-ai/commit/871c7aeec5dfed2138655ccbccbf15c6d763bae7 · [email protected]https://github.com/pydantic/pydantic-ai/pull/7437 · [email protected]https://github.com/pydantic/pydantic-ai/pull/7438 · [email protected]https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.5 · [email protected]https://github.com/pydantic/pydantic-ai/releases/tag/v2.30.0 · [email protected]https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-q2xc-rrxj-58x9 · [email protected]
EPSS history
Timeline
  • 10 OCT 03:27Z
    EPSS moved — → 0%
    epss
  • 08 OCT 16:26Z
    Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header
    cvelistv5
  • 08 OCT 16:26Z
    Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header
    cvelistv5