Vulnerability · Published Oct 8, 2026 · Assigned by GitHub_M
CVE-2026-107289Pydantic AI: SSRF cloud-metadata blocklist bypass via IPv6 zone identifier (incomplete fix for CVE-2026-46678 and CVE-2026-48782)
Medium 6.8
In plain English
A medium-severity server-side request forgery in pydantic-ai from pydantic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.56.0 until 1.107.6 and 2.44.0, applications that opt attacker-influenced URLs into local network access through FileUrl with force_download='allow-local' or web_fetch_tool with allow_local_urls=True can bypass the cloud-metadata blocklist by appending an IPv6 zone identifier to an IPv6 metadata address. IPv6Address equality and hashing include the zone identifier, so the blocklist comparison fails even though the network stack ignores the zone on a non-link-local destination and reaches the metadata service, potentially exposing cloud IAM credentials. The opt-in settings are disabled by default, and the issue requires an IPv6-enabled environment. This issue is fixed in versions 1.107.6 and 2.44.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | pydantic-ai | 1.107.6 | GHSA-vmxc-h2x2-jmf3 |
| PyPI | pydantic-ai | 2.44.0 | GHSA-vmxc-h2x2-jmf3 |
| PyPI | pydantic-ai | 1.107.6, 2.44.0 | PYSEC-2026-4282 |
| PyPI | pydantic-ai-slim | 1.107.6 | GHSA-vmxc-h2x2-jmf3 |
| PyPI | pydantic-ai-slim | 2.44.0 | GHSA-vmxc-h2x2-jmf3 |
| PyPI | pydantic-ai-slim | 1.107.6, 2.44.0 | PYSEC-2026-4291 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| pydantic | pydantic-ai | >= 1.56.0, < 1.107.6>= 2.0.0b1, < 2.44.0 |
| pydantic | pydantic-ai-slim | >= 1.56.0, < 1.107.6>= 2.0.0b1, < 2.44.0 |
Weakness: CWE-918, CWE-1289 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
References
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-vmxc-h2x2-jmf3 x_refsource_CONFIRM
- https://github.com/pydantic/pydantic-ai/pull/8401 x_refsource_MISC
- https://github.com/pydantic/pydantic-ai/pull/8402 x_refsource_MISC
- https://github.com/pydantic/pydantic-ai/commit/02157e1b87bd45d3f2e111ce07afdf89f9fb0e5b x_refsource_MISC
- https://github.com/pydantic/pydantic-ai/commit/4da70591460f51a8c4f128eaeef70a33340dbd55 x_refsource_MISC
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.6 x_refsource_MISC
- https://github.com/pydantic/pydantic-ai/releases/tag/v2.44.0 x_refsource_MISC