CVE-2026-107287
mediumPydantic AI is a Python agent framework for building applications and workflows with Generative AI.
Vendor / product: Pydantic — pydantic ai
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/pydantic/pydantic-ai/commit/2b247add4950bef61d352e7ca8aefbd20539180c security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/commit/2fd38792693da00a3ca5412aeffb436787af3545 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/pull/8984 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/pull/8985 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.7 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.52.0 security-advisories@github.com
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-v36g-jcw9-x7cw security-advisories@github.com