{"id":"CVE-2026-48782","published":"2026-06-16T22:49:26Z","modified":"2026-06-17T14:22:48Z","title":"pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of…","vendor":"pydantic","product":"pydantic-ai","tier":"tail","description":{"text":"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.","provenance":"source","from":"CVE.org"},"cvss":{"score":6.8,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.00401,"percentile":0.34206,"provenance":"source"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"references":[{"url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/pydantic/pydantic-ai/pull/5596","tags":["x_refsource_MISC"]},{"url":"https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4","tags":["x_refsource_MISC"]},{"url":"https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0","tags":["x_refsource_MISC"]}],"priority":{"score":11.6,"factors":[{"name":"EPSS percentile","points":6.84},{"name":"CVSS severity","points":4.76}]},"vendorSlug":"pydantic","affectedVersions":[{"vendor":"pydantic","product":"pydantic-ai","versions":[">= 1.56.0, < 1.102.0",">= 2.0.0b1, < 2.0.0b3"]},{"vendor":"pydantic","product":"pydantic-ai-slim","versions":[">= 2.0.0b1, < 2.0.0b3",">= 1.56.0, < 1.102.0"]}],"affected":[{"ecosystem":"PyPI","package":"pydantic-ai-slim","vulnerableRanges":[">=1.56.0, <1.102.0",">=2.0.0b1, <2.0.0b3"],"patched":["1.102.0","2.0.0b3"],"from":["GHSA-cg7w-rg45-pc59","PYSEC-2026-2981"],"provenance":"source"},{"ecosystem":"PyPI","package":"pydantic-ai","vulnerableRanges":[">=1.56.0, <1.102.0",">=2.0.0b1, <2.0.0b3"],"patched":["1.102.0","2.0.0b3"],"from":["GHSA-cg7w-rg45-pc59","PYSEC-2026-2977"],"provenance":"source"}],"euvd":{"id":"EUVD-2026-37512","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-pydantic-ai-cve-2026-25580","parents":[{"from":"CVE-2026-25580","to":"CVE-2026-48782","relation":"incomplete-fix","confidence":"high","kind":"lineage","evidence":[{"kind":"text","provenance":"source","relation":"incomplete-fix","quote":"This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580).","from":"CVE.org","in":"CVE-2026-48782"}]},{"from":"CVE-2026-46678","to":"CVE-2026-48782","relation":"incomplete-fix","confidence":"high","kind":"lineage","orderedBy":"description","evidence":[{"kind":"text","provenance":"source","relation":"incomplete-fix","quote":"This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580).","from":"CVE.org","in":"CVE-2026-48782"},{"kind":"similar","provenance":"machine","score":0.43,"basis":"same product + CWE + description similarity"}]}],"packageHistory":[{"cve":"CVE-2026-25640","published":"2026-02-06","fixed":"1.51.0","kev":false},{"cve":"CVE-2026-25580","published":"2026-02-06","fixed":"1.56.0","kev":false},{"cve":"CVE-2026-46678","published":"2026-07-29","fixed":"1.99.0","kev":false},{"cve":"CVE-2026-48782","published":"2026-06-16","fixed":"2.0.0b3","kev":false},{"cve":"CVE-2026-54249","published":"2026-07-29","fixed":"2.0.0b6","kev":false,"link":{"from":"CVE-2026-48782","to":"CVE-2026-54249","relation":"successor","confidence":"low","kind":"sequence","evidence":[{"kind":"version-step","provenance":"source","package":"PyPI:pydantic-ai","fromFixed":"1.102.0","toFixed":"1.106.0","daysApart":43},{"kind":"version-step","provenance":"source","package":"PyPI:pydantic-ai","fromFixed":"2.0.0b3","toFixed":"2.0.0b6","daysApart":43}]}},{"cve":"CVE-2026-107294","published":"2026-10-08","fixed":"2.24.0","kev":false},{"cve":"CVE-2026-107293","published":"2026-10-08","fixed":"2.27.1","kev":false}],"package":"PyPI:pydantic-ai"}}