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CVE-2026-107290

CVE-2026-107290 · Pydantic AI: Event loop blocked by quadratic title extraction in `web_fetch`

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.6 and 2.44.0, the local web_fetch_tool and the WebFetch local fallback process server-controlled responses with quadratic title extraction, whitespace normalization, and ordered-list numbering. An attacker-controlled page of modest size can therefore block the event loop for an extended period, stalling other agent runs and requests, while unsupported codecs or excessive HTML or JSON nesting can abort an individual run. This issue is fixed in versions 1.107.6 and 2.44.0.

CVSS 6.5 · Medium · EPSS 0.5% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • pydantic-ai

    Versions
    • >= 1.77.0, < 1.107.6: Affected
    • >= 2.0.0b1, < 2.44.0: Affected

    No fix published

  • pydantic-ai-slim

    Versions
    • >= 1.77.0, < 1.107.6: Affected
    • >= 2.0.0b1, < 2.44.0: Affected

    No fix published

  • pydantic-ai PyPI

    Versions
    • 1.100.0
    • 1.101.0
    • 1.102.0
    • 1.103.0
    • 1.104.0
    • 1.105.0
    • 1.106.0
    • 1.107.0
    • 1.107.1
    • 1.107.2
    • 1.107.4
    • 1.107.5
    • 1.77.0
    • 1.78.0
    • 1.79.0
    • 1.80.0
    • 1.81.0
    • 1.82.0
    • 1.83.0
    • 1.84.0
    • 1.84.1
    • 1.85.0
    • 1.85.1
    • 1.86.0
    • 1.86.1
    • 1.87.0
    • 1.88.0
    • 1.89.0
    • 1.89.1
    • 1.90.0
    • 1.91.0
    • 1.92.0
    • 1.93.0
    • 1.94.0
    • 1.95.0
    • 1.95.1
    • 1.96.0
    • 1.96.1
    • 1.97.0
    • 1.98.0
    • 1.99.0
    Affected ranges
    • ECOSYSTEM: ≥ 1.77.0, < 1.107.6

    Update to 1.107.6

  • pydantic-ai PyPI

    Versions
    • 2.0.0
    • 2.0.0b1
    • 2.0.0b2
    • 2.0.0b3
    • 2.0.0b4
    • 2.0.0b5
    • 2.0.0b6
    • 2.0.0b7
    • 2.1.0
    • 2.10.0
    • 2.11.0
    • 2.12.0
    • 2.13.0
    • 2.14.0
    • 2.14.1
    • 2.15.0
    • 2.16.0
    • 2.17.0
    • 2.18.0
    • 2.19.0
    • 2.2.0
    • 2.20.0
    • 2.21.0
    • 2.22.0
    • 2.23.0
    • 2.24.0
    • 2.25.0
    • 2.26.0
    • 2.27.0
    • 2.27.1
    • 2.28.0
    • 2.29.0
    • 2.3.0
    • 2.30.0
    • 2.31.0
    • 2.31.1
    • 2.32.0
    • 2.32.1
    • 2.32.2
    • 2.33.0
    • 2.34.0
    • 2.35.0
    • 2.35.1
    • 2.35.3
    • 2.36.0
    • 2.37.0
    • 2.38.0
    • 2.39.0
    • 2.4.0
    • 2.40.0
    • 2.41.0
    • 2.42.0
    • 2.43.0
    • 2.5.0
    • 2.5.1
    • 2.6.0
    • 2.7.0
    • 2.8.0
    • 2.9.0
    • 2.9.1
    Affected ranges
    • ECOSYSTEM: ≥ 2.0.0b1, < 2.44.0

    Update to 2.44.0

  • pydantic-ai-slim PyPI

    Versions
    • 1.100.0
    • 1.101.0
    • 1.102.0
    • 1.103.0
    • 1.104.0
    • 1.105.0
    • 1.106.0
    • 1.107.0
    • 1.107.1
    • 1.107.2
    • 1.107.4
    • 1.107.5
    • 1.77.0
    • 1.78.0
    • 1.79.0
    • 1.80.0
    • 1.81.0
    • 1.82.0
    • 1.83.0
    • 1.84.0
    • 1.84.1
    • 1.85.0
    • 1.85.1
    • 1.86.0
    • 1.86.1
    • 1.87.0
    • 1.88.0
    • 1.89.0
    • 1.89.1
    • 1.90.0
    • 1.91.0
    • 1.92.0
    • 1.93.0
    • 1.94.0
    • 1.95.0
    • 1.95.1
    • 1.96.0
    • 1.96.1
    • 1.97.0
    • 1.98.0
    • 1.99.0
    Affected ranges
    • ECOSYSTEM: ≥ 1.77.0, < 1.107.6

    Update to 1.107.6

  • pydantic-ai-slim PyPI

    Versions
    • 2.0.0
    • 2.0.0b1
    • 2.0.0b2
    • 2.0.0b3
    • 2.0.0b4
    • 2.0.0b5
    • 2.0.0b6
    • 2.0.0b7
    • 2.1.0
    • 2.10.0
    • 2.11.0
    • 2.12.0
    • 2.13.0
    • 2.14.0
    • 2.14.1
    • 2.15.0
    • 2.16.0
    • 2.17.0
    • 2.18.0
    • 2.19.0
    • 2.2.0
    • 2.20.0
    • 2.21.0
    • 2.22.0
    • 2.23.0
    • 2.24.0
    • 2.25.0
    • 2.26.0
    • 2.27.0
    • 2.27.1
    • 2.28.0
    • 2.29.0
    • 2.3.0
    • 2.30.0
    • 2.31.0
    • 2.31.1
    • 2.32.0
    • 2.32.1
    • 2.32.2
    • 2.33.0
    • 2.34.0
    • 2.35.0
    • 2.35.1
    • 2.35.3
    • 2.36.0
    • 2.37.0
    • 2.38.0
    • 2.39.0
    • 2.4.0
    • 2.40.0
    • 2.41.0
    • 2.42.0
    • 2.43.0
    • 2.5.0
    • 2.5.1
    • 2.6.0
    • 2.7.0
    • 2.8.0
    • 2.9.0
    • 2.9.1
    Affected ranges
    • ECOSYSTEM: ≥ 2.0.0b1, < 2.44.0

    Update to 2.44.0

  • pydantic-ai PyPI

    Versions
    • 1.100.0
    • 1.101.0
    • 1.102.0
    • 1.103.0
    • 1.104.0
    • 1.105.0
    • 1.106.0
    • 1.107.0
    • 1.107.1
    • 1.107.2
    • 1.107.4
    • 1.107.5
    • 1.77.0
    • 1.78.0
    • 1.79.0
    • 1.80.0
    • 1.81.0
    • 1.82.0
    • 1.83.0
    • 1.84.0
    • 1.84.1
    • 1.85.0
    • 1.85.1
    • 1.86.0
    • 1.86.1
    • 1.87.0
    • 1.88.0
    • 1.89.0
    • 1.89.1
    • 1.90.0
    • 1.91.0
    • 1.92.0
    • 1.93.0
    • 1.94.0
    • 1.95.0
    • 1.95.1
    • 1.96.0
    • 1.96.1
    • 1.97.0
    • 1.98.0
    • 1.99.0
    • 2.0.0
    • 2.0.0b1
    • 2.0.0b2
    • 2.0.0b3
    • 2.0.0b4
    • 2.0.0b5
    • 2.0.0b6
    • 2.0.0b7
    • 2.1.0
    • 2.10.0
    • 2.11.0
    • 2.12.0
    • 2.13.0
    • 2.14.0
    • 2.14.1
    • 2.15.0
    • 2.16.0
    • 2.17.0
    • 2.18.0
    • 2.19.0
    • 2.2.0
    • 2.20.0
    • 2.21.0
    • 2.22.0
    • 2.23.0
    • 2.24.0
    • 2.25.0
    • 2.26.0
    • 2.27.0
    • 2.27.1
    • 2.28.0
    • 2.29.0
    • 2.3.0
    • 2.30.0
    • 2.31.0
    • 2.31.1
    • 2.32.0
    • 2.32.1
    • 2.32.2
    • 2.33.0
    • 2.34.0
    • 2.35.0
    • 2.35.1
    • 2.35.3
    • 2.36.0
    • 2.37.0
    • 2.38.0
    • 2.39.0
    • 2.4.0
    • 2.40.0
    • 2.41.0
    • 2.42.0
    • 2.43.0
    • 2.5.0
    • 2.5.1
    • 2.6.0
    • 2.7.0
    • 2.8.0
    • 2.9.0
    • 2.9.1
    Affected ranges
    • ECOSYSTEM: ≥ 1.77.0, < 1.107.6 ∪ ≥ 2.0.0b1, < 2.44.0

    Update to 1.107.6; Update to 2.44.0

  • pydantic-ai-slim PyPI

    Versions
    • 1.100.0
    • 1.101.0
    • 1.102.0
    • 1.103.0
    • 1.104.0
    • 1.105.0
    • 1.106.0
    • 1.107.0
    • 1.107.1
    • 1.107.2
    • 1.107.4
    • 1.107.5
    • 1.77.0
    • 1.78.0
    • 1.79.0
    • 1.80.0
    • 1.81.0
    • 1.82.0
    • 1.83.0
    • 1.84.0
    • 1.84.1
    • 1.85.0
    • 1.85.1
    • 1.86.0
    • 1.86.1
    • 1.87.0
    • 1.88.0
    • 1.89.0
    • 1.89.1
    • 1.90.0
    • 1.91.0
    • 1.92.0
    • 1.93.0
    • 1.94.0
    • 1.95.0
    • 1.95.1
    • 1.96.0
    • 1.96.1
    • 1.97.0
    • 1.98.0
    • 1.99.0
    • 2.0.0
    • 2.0.0b1
    • 2.0.0b2
    • 2.0.0b3
    • 2.0.0b4
    • 2.0.0b5
    • 2.0.0b6
    • 2.0.0b7
    • 2.1.0
    • 2.10.0
    • 2.11.0
    • 2.12.0
    • 2.13.0
    • 2.14.0
    • 2.14.1
    • 2.15.0
    • 2.16.0
    • 2.17.0
    • 2.18.0
    • 2.19.0
    • 2.2.0
    • 2.20.0
    • 2.21.0
    • 2.22.0
    • 2.23.0
    • 2.24.0
    • 2.25.0
    • 2.26.0
    • 2.27.0
    • 2.27.1
    • 2.28.0
    • 2.29.0
    • 2.3.0
    • 2.30.0
    • 2.31.0
    • 2.31.1
    • 2.32.0
    • 2.32.1
    • 2.32.2
    • 2.33.0
    • 2.34.0
    • 2.35.0
    • 2.35.1
    • 2.35.3
    • 2.36.0
    • 2.37.0
    • 2.38.0
    • 2.39.0
    • 2.4.0
    • 2.40.0
    • 2.41.0
    • 2.42.0
    • 2.43.0
    • 2.5.0
    • 2.5.1
    • 2.6.0
    • 2.7.0
    • 2.8.0
    • 2.9.0
    • 2.9.1
    Affected ranges
    • ECOSYSTEM: ≥ 1.77.0, < 1.107.6 ∪ ≥ 2.0.0b1, < 2.44.0

    Update to 1.107.6; Update to 2.44.0

Original sources

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