---
id: CVE-2026-107287
title: >-
  Pydantic AI is a Python agent framework for building applications and
  workflows with Generative AI
summary: >-
  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 durin…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-407
vendor: pydantic
product: pydantic-ai
affected:
  - 'pydantic-ai >= 1.77.0, < 1.107.7'
  - 'pydantic-ai >= 2.0.0b1, < 2.52.0'
  - 'pydantic-ai-slim >= 1.77.0, < 1.107.7'
  - 'pydantic-ai-slim >= 2.0.0b1, < 2.52.0'
patched:
  - pydantic-ai 1.107.7
  - pydantic-ai 2.52.0
  - pydantic-ai-slim 1.107.7
  - pydantic-ai-slim 2.52.0
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:05:00.260'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-107287'
references:
  - url: >-
      https://github.com/pydantic/pydantic-ai/commit/2b247add4950bef61d352e7ca8aefbd20539180c
    label: security-advisories@github.com
  - url: >-
      https://github.com/pydantic/pydantic-ai/commit/2fd38792693da00a3ca5412aeffb436787af3545
    label: security-advisories@github.com
  - url: 'https://github.com/pydantic/pydantic-ai/pull/8984'
    label: security-advisories@github.com
  - url: 'https://github.com/pydantic/pydantic-ai/pull/8985'
    label: security-advisories@github.com
  - url: 'https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.7'
    label: security-advisories@github.com
  - url: 'https://github.com/pydantic/pydantic-ai/releases/tag/v2.52.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-v36g-jcw9-x7cw
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-v36g-jcw9-x7cw'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
aliases:
  - GHSA-v36g-jcw9-x7cw
ecosystem: pip
ingestedAt: '2026-10-08T16:52:14.772Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-107287)

Affected packages:

- `pydantic-ai >= 1.77.0, < 1.107.7`
- `pydantic-ai >= 2.0.0b1, < 2.52.0`
- `pydantic-ai-slim >= 1.77.0, < 1.107.7`
- `pydantic-ai-slim >= 2.0.0b1, < 2.52.0`

Patched in:

- `pydantic-ai 1.107.7`
- `pydantic-ai 2.52.0`
- `pydantic-ai-slim 1.107.7`
- `pydantic-ai-slim 2.52.0`

Source: https://github.com/advisories/GHSA-v36g-jcw9-x7cw