pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)
Summary
| CVE | CVE-2026-48782 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-17 13:20:43 UTC |
| Updated | 2026-06-17 16:28:24 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 6.8 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N |
| 3.1 | CNA | DECLARED | 6.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
ChangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Pydantic | Pydantic-ai | affected >= 1.56.0, < 1.102.0 | Not specified |
| CNA | Pydantic | Pydantic-ai | affected >= 2.0.0b1, < 2.0.0b3 | Not specified |
| CNA | Pydantic | Pydantic-ai-slim | affected >= 2.0.0b1, < 2.0.0b3 | Not specified |
| CNA | Pydantic | Pydantic-ai-slim | affected >= 1.56.0, < 1.102.0 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59 | [email protected] | github.com | |
| github.com/pydantic/pydantic-ai/pull/5596 | [email protected] | github.com | |
| github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7... | [email protected] | github.com | |
| github.com/pydantic/pydantic-ai/releases/tag/v1.102.0 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.