Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header
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.
CVE-2026-107292
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-107292
pydantic-ai
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
pydantic-ai-slim
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "pydantic",
"product": "pydantic-ai",
"versions": [
{
"status": "affected",
"version": ">= 1.34.0, < 2.0.0b1"
},
{
"status": "affected",
"version": ">= 2.0.0b1, < 2.30.0"
}
]
},
{
"vendor": "pydantic",
"product": "pydantic-ai-slim",
"versions": [
{
"status": "affected",
"version": ">= 1.34.0, < 2.0.0b1"
},
{
"status": "affected",
"version": ">= 2.0.0b1, < 2.30.0"
}
]
}
]- Related CVEs
- CVE-2026-107292
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #21322 · Revision 1
- Added to Heist Feed
- Publisher date