Pydantic AI up to 1.107.5/2.43.x WebFetch resource consumption

Summaryinfo

A vulnerability marked as problematic has been reported in Pydantic AI up to 1.107.5/2.43.x. Impacted is an unknown function of the component WebFetch. The manipulation leads to resource consumption. This vulnerability is referenced as CVE-2026-107290. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Pydantic AI up to 1.107.5/2.43.x. It has been rated as problematic. This issue affects an unknown code of the component WebFetch. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-107290 since 10/07/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 1.107.6 or 2.44.0 eliminates this vulnerability.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• Pydantic

Name

• AI

Version

• 1.107.0
• 1.107.1
• 1.107.2
• 1.107.3
• 1.107.4
• 1.107.5
• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.40
• 2.41
• 2.42
• 2.43

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

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Entryinfo

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