CVE-2026-107295
Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): a website visited by the developer can trigger agent runs and server-side tool execution on the local chat endpoint
Impact
Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 1.107.4 and 2.28.0, the Agent.to_web() and clai web development chat endpoint has missing request content-type validation. A website visited by a developer can submit a browser-compatible request to a loopback-hosted chat server, causing the served agent to run and execute tools with the privileges and credentials of the local process; client-relayed approval decisions also leave requires_approval=True tools exposed. Binding to localhost does not prevent a browser page from reaching the loopback address. This issue is fixed in versions 1.107.4 and 2.28.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pydantic-ai | >= 1.34.0, < 1.107.4 | 1.107.4 |
| pip | pydantic-ai-slim | >= 1.34.0, < 1.107.4 | 1.107.4 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pydantic | Pydantic Ai | from 1.34.0 before 1.107.4 from 2.0.0 before 2.28.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-h4xc-3qfq-jf93
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-h4xc-3qfq-jf93
- https://github.com/pydantic/pydantic-ai/pull/7382
- https://github.com/pydantic/pydantic-ai/pull/7383
- https://github.com/pydantic/pydantic-ai/commit/d2690201a1834005d382dbf5c47e0ed94ef8bf46
- https://github.com/pydantic/pydantic-ai/commit/dd2abbdfa029c9ad138e7cc0edd2eaeaf9ed69c0
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.4
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.28.0