GHSA-h4xc-3qfq-jf93
Suggest an improvement- Source
- https://github.com/advisories/GHSA-h4xc-3qfq-jf93
- Import Source
- https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-h4xc-3qfq-jf93/GHSA-h4xc-3qfq-jf93.json
- JSON Data
- https://api.osv.dev/v1/vulns/GHSA-h4xc-3qfq-jf93
- Aliases
- Published
- 2026-10-08T17:16:36Z
- Modified
- 2026-10-08T17:31:46Z
- Severity
-
- 7.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L CVSS Calculator
- Summary
- 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
- Details
-
Summary
The Pydantic AI development web chat UI (
Agent.to_web(),clai web) did not check the content type of requests to its chat endpoint. This allowed a website visited by a developer to submit a request to a chat UI running on that developer's machine, causing the served agent to run and to execute its tools with the privileges and credentials of the local process.Binding the web UI to localhost — the default — does not prevent this, because a page open in the developer's browser can reach the loopback address.
Impact
Applications and developers serving an agent through
Agent.to_web()orclai web. The consequences depend on the tools the served agent exposes, and can include data disclosure as well as unwanted tool side effects. Tools markedrequires_approval=Truewere not protected either, because the endpoint trusts approval decisions relayed by the client.Mitigation
Upgrade to a patched version. The chat endpoint now requires
Content-Type: application/jsonand rejects other requests before the request body is parsed and before the agent runs. The bundled chat UI already sends this header; scripts and other non-browser clients that call the endpoint directly may need to be updated to send it.If you cannot upgrade, don't run the web UI while browsing untrusted sites, stop it when you aren't using it, and don't serve an agent with side-effecting tools through it.
Credits
- Thai Son Dinh from VinSOC Labs (R&D)
- Database specific
{ "cwe_ids": [ "CWE-346", "CWE-352" ], "github_reviewed": true, "github_reviewed_at": "2026-10-08T17:16:36Z", "nvd_published_at": null, "severity": "HIGH" }- References
-
- 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
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.4
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.28.0
Affected packages
PyPI / pydantic-ai
Package
- Name
- pydantic-ai
- View open source insights on deps.dev
- Purl
- pkg:pypi/pydantic-ai
Affected versions
1.*
PyPI / pydantic-ai
Package
- Name
- pydantic-ai
- View open source insights on deps.dev
- Purl
- pkg:pypi/pydantic-ai
PyPI / pydantic-ai-slim
Package
- Name
- pydantic-ai-slim
- View open source insights on deps.dev
- Purl
- pkg:pypi/pydantic-ai-slim
Affected versions
1.*
PyPI / pydantic-ai-slim
Package
- Name
- pydantic-ai-slim
- View open source insights on deps.dev
- Purl
- pkg:pypi/pydantic-ai-slim