medium6.5
CVE-2026-107287
Pydantic AI is a Python agent framework for building applications and workflows with Generative AI.
Impact
Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.7 and 2.52.0, the local web_fetch_tool and the WebFetch local fallback can consume excessive CPU and memory during HTML-to-Markdown conversion of attacker-controlled HTML containing deeply nested block elements. Conversion repeatedly reprocesses accumulated text and can greatly expand intermediate output before the returned-content limit is applied, allowing a model-directed fetch to delay other work in the process. Provider-native web fetching is not affected. This issue is fixed in versions 1.107.7 and 2.52.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | pydantic-ai | >= 1.77.0, < 1.107.7 | 1.107.7 |
| pip | pydantic-ai-slim | >= 1.77.0, < 1.107.7 | 1.107.7 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pydantic | Pydantic Ai | from 1.77.0 before 1.107.7 from 2.0.0 before 2.52.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-v36g-jcw9-x7cw
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-v36g-jcw9-x7cw
- https://github.com/pydantic/pydantic-ai/pull/8984
- https://github.com/pydantic/pydantic-ai/pull/8985
- https://github.com/pydantic/pydantic-ai/commit/2b247add4950bef61d352e7ca8aefbd20539180c
- https://github.com/pydantic/pydantic-ai/commit/2fd38792693da00a3ca5412aeffb436787af3545
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.7
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.52.0