{"id":"CVE-2026-48782","aliases":["GHSA-cg7w-rg45-pc59","PYSEC-2026-2977","PYSEC-2026-2981"],"url":"https://o3.security/vulnerability/CVE-2026-48782","summary":"pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)","details":"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.","published":"2026-06-16T22:49:26.750Z","modified":"2026-08-08T03:48:02.331145237Z","cvss":{"score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"pydantic-ai-slim","fixedVersion":"1.102.0"},{"ecosystem":"PyPI","name":"pydantic-ai","fixedVersion":"1.102.0"},{"ecosystem":"PyPI","name":"pydantic-ai","fixedVersion":"2.0.0b3"},{"ecosystem":"PyPI","name":"pydantic-ai-slim","fixedVersion":"2.0.0b3"}],"fix":{"url":"https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4","label":"pydantic/pydantic-ai@1add061"},"references":[{"type":"WEB","url":"https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48782.json"},{"type":"ADVISORY","url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48782"},{"type":"FIX","url":"https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4"},{"type":"FIX","url":"https://github.com/pydantic/pydantic-ai/pull/5596"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-08T03:48:02.331145237Z"}}