Pydantic AI affected by Stored XSS via Path Traversal in Web UI CDN URL_CVE-2026-25640

{
    "lastseen": "",
    "description": "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 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.",
    "published": "2026-02-06T20:01:53.892Z",
    "modified": "2026-02-06T20:16:23.201Z",
    "type": "cve",
    "title": "Pydantic AI affected by Stored XSS via Path Traversal in Web UI CDN URL",
    "source": "GitHub_M",
    "references": "https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-wjp5-868j-wqv7\nhttps://github.com/pydantic/pydantic-ai/releases/tag/v1.51.0",
    "id": "CVE-2026-25640",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22",
        "CWE-79"
    ],
    "cvelist": null,
    "sourceData": "pydantic pydantic-ai >= 1.34.0, < 1.51.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "pydantic-ai",
    "version": ">= 1.34.0, < 1.51.0",
    "vendor": "pydantic",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}