Pydantic AI affected by Stored XSS via Path Traversal in Web UI CDN URL (pydantic pydantic-ai)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.38 % · percentile 32 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-22 — Improper Limitation of a Pathname to a Restricted Directory
- CWE-79 — Improper Neutralization of Input During Web Page Generation
References
- https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-wjp5-868j-wqv7
- https://github.com/pydantic/pydantic-ai/releases/tag/v1.51.0
- https://access.redhat.com/security/cve/CVE-2026-25640
- https://bugzilla.redhat.com/show_bug.cgi?id=2437753
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25640.json
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N | GitHub_M |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N | redhat-SADP |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | MEDIUM 5.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-wjp5-868j-wqv7 — Pydantic AI has Stored XSS via Path Traversal in Web UI CDN URL
- PYSEC-2026-2979 — Pydantic AI has Stored XSS via Path Traversal in Web UI CDN URL
- PYSEC-2026-2983 — Pydantic AI has Stored XSS via Path Traversal in Web UI CDN URL
European references
- ENISA EUVD · EUVD-2026-5593
- GCVE · GCVE-0-2026-25640
Affected configurations (NVD CPE)
cpe:2.3:a:pydantic:pydantic_ai:*:*:*:*:*:python:*:*≥ 1.34.0 < 1.51.0
Affected products
| Product | Versions |
|---|---|
| pydantic · pydantic-ai | affected >= 1.34.0, < 1.51.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |