{"id":"CVE-2026-25640","title":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI","summary":"Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 to before 1.51.0,  a path traversal vulnerability in the Pydantic AI web UI allows an attacker to serve arbitrary JavaScript …","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N","cwe":["CWE-22","CWE-79","CWE-22"],"vendor":"pydantic","product":"pydantic_ai","affected":["pydantic_ai >= 1.34.0, < 1.51.0"],"patched":["pydantic_ai 1.51.0"],"published":"2026-02-06","updated":"2026-06-30","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-25640","references":[{"url":"https://github.com/pydantic/pydantic-ai/releases/tag/v1.51.0","label":"security-advisories@github.com"},{"url":"https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-wjp5-868j-wqv7","label":"security-advisories@github.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-25640","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2437753","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25640.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}],"tags":["nvd"],"epss":0.00336,"epssPercentile":0.27134,"ingestedAt":"2026-07-03T18:53:52.175Z","slug":"CVE-2026-25640","body":"## Overview\n\nPydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 to before 1.51.0,  a path traversal vulnerability in the Pydantic AI web UI allows an attacker to serve arbitrary JavaScript in the context of the application by crafting a malicious URL. In affected versions, the CDN URL is constructed using a version query parameter from the request URL. This parameter is not validated, allowing path traversal sequences that cause the server to fetch and serve attacker-controlled HTML/JavaScript from an arbitrary source on the same CDN, instead of the legitimate chat UI package. If a victim clicks the link or visits it via an iframe, attacker-controlled code executes in their browser, enabling theft of chat history and other client-side data. This vulnerability only affects applications that use Agent.to_web to serve a chat interface and clai web to serve a chat interface from the CLI. These are typically run locally (on localhost), but may also be deployed on a remote server. This vulnerability is fixed in 1.51.0.\n\n## Affected\n\n- `pydantic_ai >= 1.34.0, < 1.51.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `pydantic_ai 1.51.0`","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}