{"id":"CVE-2026-48782","state":"PUBLISHED","title":"pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)","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.","publishedAt":"2026-06-16T22:49:26.750Z","updatedAt":"2026-06-17T14:22:48.236Z","severity":{"score":6.8,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["pydantic pydantic-ai","pydantic pydantic-ai-slim"],"affected":[{"vendor":"pydantic","product":"pydantic-ai","versions":[{"version":">= 1.56.0, < 1.102.0","status":"affected"},{"version":">= 2.0.0b1, < 2.0.0b3","status":"affected"}]},{"vendor":"pydantic","product":"pydantic-ai-slim","versions":[{"version":">= 2.0.0b1, < 2.0.0b3","status":"affected"},{"version":">= 1.56.0, < 1.102.0","status":"affected"}]}],"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"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48782.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48782","state":"PUBLISHED","datePublished":"2026-06-16T22:49:26.750Z","dateUpdated":"2026-06-17T14:22:48.236Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-22T20:18:20.365Z"},"containers":{"cna":{"title":"pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"pydantic","product":"pydantic-ai","versions":[{"version":">= 1.56.0, < 1.102.0","status":"affected"},{"version":">= 2.0.0b1, < 2.0.0b3","status":"affected"}]},{"vendor":"pydantic","product":"pydantic-ai-slim","versions":[{"version":">= 2.0.0b1, < 2.0.0b3","status":"affected"},{"version":">= 1.56.0, < 1.102.0","status":"affected"}]}],"references":[{"url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59","name":"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","name":"https://github.com/pydantic/pydantic-ai/pull/5596","tags":["x_refsource_MISC"]},{"url":"https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4","name":"https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4","tags":["x_refsource_MISC"]},{"url":"https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0","name":"https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.8,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-16T22:49:26.750Z"},"source":{"advisory":"GHSA-cg7w-rg45-pc59","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-17T14:22:37.373304Z","id":"CVE-2026-48782","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-17T14:22:48.236Z"}}]}}}