pydantic AI up to 1.98.x Cloud Metadata Blocklist force_download encoding error

Summaryinfo

A vulnerability was found in pydantic AI up to 1.98.x. It has been classified as critical. This vulnerability affects unknown code of the component Cloud Metadata Blocklist. This manipulation of the argument force_download causes encoding error. This vulnerability is tracked as CVE-2026-46678. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in pydantic AI up to 1.98.x and classified as critical. Affected by this vulnerability is an unknown code block of the component Cloud Metadata Blocklist. The manipulation of the argument force_download with an unknown input leads to a encoding error vulnerability. The CWE definition for the vulnerability is CWE-172. The product does not properly encode or decode the data, resulting in unexpected values. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Pydantic AI is a Python agent framework for building Generative AI applications. In versions 1.56.0 through 1.98.0, when an application opts a URL into force_download='allow-local' (disabling the default block on private/internal IPs), the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form (IPv4-mapped IPv6, 6to4, or NAT64), exposing cloud IAM short-term credentials on dual-stack or translated networks. This is an incomplete fix of GHSA-2jrp-274c-jhv3 / CVE-2026-25580, whose remediation did not hold for IPv6-encoded forms of the metadata IPs. An application is affected only if it explicitly opts a FileUrl (ImageUrl, AudioUrl, VideoUrl, DocumentUrl) into force_download='allow-local' on a URL influenced by untrusted input; it is not affected when using bundled integrations to ingest user input (Agent.to_web / clai web, VercelAIAdapter, AGUIAdapter / Agent.to_ag_ui), since they do not propagate force_download from external data, nor when downloading only from developer-controlled URLs. This issue has been fixed in version 1.99.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-46678 since 05/15/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available.

Upgrading to version 1.99.0 eliminates this vulnerability.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• pydantic

Name

• AI

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.37
• 1.38
• 1.39
• 1.40
• 1.41
• 1.42
• 1.43
• 1.44
• 1.45
• 1.46
• 1.47
• 1.48
• 1.49
• 1.50
• 1.51
• 1.52
• 1.53
• 1.54
• 1.55
• 1.56
• 1.57
• 1.58
• 1.59
• 1.60
• 1.61
• 1.62
• 1.63
• 1.64
• 1.65
• 1.66
• 1.67
• 1.68
• 1.69
• 1.70
• 1.71
• 1.72
• 1.73
• 1.74
• 1.75
• 1.76
• 1.77
• 1.78
• 1.79
• 1.80
• 1.81
• 1.82
• 1.83
• 1.84
• 1.85
• 1.86
• 1.87
• 1.88
• 1.89
• 1.90
• 1.91
• 1.92
• 1.93
• 1.94
• 1.95
• 1.96
• 1.97
• 1.98

CPE 2.3info

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