CVE-2026-46678: Pydantic Pydantic AI SSRF bypass in cloud-metadata blocklist

CVE-2026-46678 · Severity: medium · CVSS 6.8 · Published 2026-07-29

Pydantic AI is a framework used to build artificial intelligence applications. A security flaw exists where the system's protections against accessing sensitive internal data can be bypassed if a developer specifically enables local file downloads for user-provided links. If exploited, an attacker could steal temporary security credentials from the cloud environment where the application is running, potentially leading to unauthorized access to other cloud resources.

Technologies: Pydantic AI Slim, pydantic-ai (PyPI), pydantic-ai-slim (PyPI). Vendors: Pydantic, PyPI.

Quick answers

Is CVE-2026-46678 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-46678 being exploited in the wild.
How severe is CVE-2026-46678?
Medium severity, with a CVSS score of 6.8, published 29 July 2026.
Which products and versions are affected?
pydantic-ai (PyPI) >= 1.56.0, < 1.99.0, ECOSYSTEM:introduced=1.56.0,fixed=1.99.0; pydantic-ai-slim (PyPI) >= 1.56.0, < 1.99.0, ECOSYSTEM:introduced=1.56.0,fixed=1.99.0.
Is there a fix for CVE-2026-46678?
Yes. pydantic-ai (PyPI): upgrade to 1.99.0 or later; pydantic-ai-slim (PyPI): upgrade to 1.99.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-46678 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-46678?
Check whether you run Pydantic AI Slim, pydantic-ai (PyPI) or pydantic-ai-slim (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • pydantic-ai (PyPI): upgrade to 1.99.0 or later
    pip install "pydantic-ai>=1.99.0"
  • pydantic-ai-slim (PyPI): upgrade to 1.99.0 or later
    pip install "pydantic-ai-slim>=1.99.0"

Technical details

This vulnerability is a Server-Side Request Forgery (SSRF) bypass resulting from an incomplete fix for a previous issue. When an application explicitly sets 'force_download=allow-local' on a FileUrl influenced by untrusted input, the framework's blocklist for cloud metadata endpoints can be bypassed. Attackers can use IPv6 transition forms (such as IPv4-mapped IPv6, 6to4, or NAT64) to represent blocked IPv4 metadata addresses. On dual-stack or translated networks, these requests are routed to the underlying IPv4 metadata service, allowing the retrieval of IAM short-term credentials. The issue is fixed in version 1.99.0 by normalizing IPv6 transition forms during URL validation.

Affected products

  • pydantic pydantic-ai >= 1.56.0, < 1.99.0
  • pydantic pydantic-ai-slim >= 1.56.0, < 1.99.0

Identifiers

  • CVE-2026-46678
  • GHSA-cqp8-fcvh-x7r3
  • PYSEC-2026-2978
  • PYSEC-2026-2982

Timeline

  • 2026-05-19: patched: Version 1.99.0 released
  • 2026-05-20: advisory: GitHub Security Advisory published
  • 2026-07-29: disclosed: CVE-2026-46678 published to NVD

References

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