Vulnerability Details CVE-2026-107288
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 compare blocked_domains entries with a URL hostname before both values are normalized to the form used by getaddrinfo. An attacker-influenced model can use an equivalent IDNA spelling, non-ASCII label separator, case variation, or trailing root label that resolves to a blocked host but does not match the configured string, causing the application to fetch that host with its own privileges. allowed_domains fails closed for unmatched spellings, and private-IP and cloud-metadata protections remain effective. This issue is fixed in versions 1.107.6 and 2.44.0.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 29.9%
CVSS Severity
CVSS v3 Score 3.7
References
- https://github.com/pydantic/pydantic-ai/commit/490335f8e2322e143a79337ddca9410e0176c812
- https://github.com/pydantic/pydantic-ai/commit/a9dab92099d0ef9d5d4aa34ccac8a6f1b0e51284
- https://github.com/pydantic/pydantic-ai/commit/c1f212a084cbfa0012f2044cdb4731d214b3b983
- https://github.com/pydantic/pydantic-ai/pull/8407
- https://github.com/pydantic/pydantic-ai/pull/8409
- https://github.com/pydantic/pydantic-ai/pull/8421
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.6
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.44.0
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-22h6-qm39-v87j
Products affected by CVE-2026-107288
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cpe:2.3:a:pydantic:pydantic_ai:1.100.0
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cpe:2.3:a:pydantic:pydantic_ai:1.101.0
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cpe:2.3:a:pydantic:pydantic_ai:1.102.0
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cpe:2.3:a:pydantic:pydantic_ai:1.103.0
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cpe:2.3:a:pydantic:pydantic_ai:1.104.0
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cpe:2.3:a:pydantic:pydantic_ai:1.105.0
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cpe:2.3:a:pydantic:pydantic_ai:1.106.0
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cpe:2.3:a:pydantic:pydantic_ai:1.107.0
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cpe:2.3:a:pydantic:pydantic_ai:1.107.1
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cpe:2.3:a:pydantic:pydantic_ai:1.77.0
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cpe:2.3:a:pydantic:pydantic_ai:1.78.0
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cpe:2.3:a:pydantic:pydantic_ai:1.79.0
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cpe:2.3:a:pydantic:pydantic_ai:1.80.0
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cpe:2.3:a:pydantic:pydantic_ai:1.81.0
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cpe:2.3:a:pydantic:pydantic_ai:1.82.0
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cpe:2.3:a:pydantic:pydantic_ai:1.83.0
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cpe:2.3:a:pydantic:pydantic_ai:1.84.0
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cpe:2.3:a:pydantic:pydantic_ai:1.84.1
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cpe:2.3:a:pydantic:pydantic_ai:1.85.0
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cpe:2.3:a:pydantic:pydantic_ai:1.85.1
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cpe:2.3:a:pydantic:pydantic_ai:1.86.0
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cpe:2.3:a:pydantic:pydantic_ai:1.86.1
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cpe:2.3:a:pydantic:pydantic_ai:1.87.0
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cpe:2.3:a:pydantic:pydantic_ai:1.88.0
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cpe:2.3:a:pydantic:pydantic_ai:1.89.0
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cpe:2.3:a:pydantic:pydantic_ai:1.89.1
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cpe:2.3:a:pydantic:pydantic_ai:1.90.0
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cpe:2.3:a:pydantic:pydantic_ai:1.91.0
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cpe:2.3:a:pydantic:pydantic_ai:1.92.0
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cpe:2.3:a:pydantic:pydantic_ai:1.93.0
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cpe:2.3:a:pydantic:pydantic_ai:1.94.0
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cpe:2.3:a:pydantic:pydantic_ai:1.95.0
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cpe:2.3:a:pydantic:pydantic_ai:1.95.1
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cpe:2.3:a:pydantic:pydantic_ai:1.96.0
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cpe:2.3:a:pydantic:pydantic_ai:1.96.1
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cpe:2.3:a:pydantic:pydantic_ai:1.97.0
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cpe:2.3:a:pydantic:pydantic_ai:1.98.0
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cpe:2.3:a:pydantic:pydantic_ai:1.99.0
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cpe:2.3:a:pydantic:pydantic_ai:2.0.0