{"id":"CVE-2026-107288","revision":"51b42d082b2746b29e036c8af9cecbc3","records":[{"revision":"51b42d082b2746b29e036c8af9cecbc3","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-107288","aliases":[],"title":"Pydantic AI: web_fetch_tool blocked_domains bypass via a hostname the resolver normalizes differently","description":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.6 and 2.44.0, the local web_fetch_tool and the WebFetch local fallback compare blocked_domains entries with a URL hostname before both values are normalized to the form used by getaddrinfo. An attacker-influenced model can use an equivalent IDNA spelling, non-ASCII label separator, case variation, or trailing root label that resolves to a blocked host but does not match the configured string, causing the application to fetch that host with its own privileges. allowed_domains fails closed for unmatched spellings, and private-IP and cloud-metadata protections remain effective. This issue is fixed in versions 1.107.6 and 2.44.0.","state":0,"publishedAt":"2026-10-08T15:18:40.047+00:00","modifiedAt":"2026-10-08T17:28:53.801+00:00","affected":[{"ecosystem":"Vendor product","name":"pydantic-ai","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"pydantic\",\n                    \"product\": \"pydantic-ai\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 1.77.0, < 1.107.6\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \">= 2.0.0b1, < 2.44.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"pydantic-ai-slim","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"pydantic\",\n                    \"product\": \"pydantic-ai-slim\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 1.77.0, < 1.107.6\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \">= 2.0.0b1, < 2.44.0\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","score":3.7,"severity":"LOW"}],"references":["https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-22h6-qm39-v87j","https://github.com/pydantic/pydantic-ai/pull/8407","https://github.com/pydantic/pydantic-ai/pull/8409","https://github.com/pydantic/pydantic-ai/pull/8421","https://github.com/pydantic/pydantic-ai/commit/490335f8e2322e143a79337ddca9410e0176c812","https://github.com/pydantic/pydantic-ai/commit/a9dab92099d0ef9d5d4aa34ccac8a6f1b0e51284","https://github.com/pydantic/pydantic-ai/commit/c1f212a084cbfa0012f2044cdb4731d214b3b983","https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.6","https://github.com/pydantic/pydantic-ai/releases/tag/v2.44.0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-107288","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-107288","identifiers":["CVE-2026-107288"]},"retained":false,"historicalAffected":[]}],"coverage":[]}