---
cve: "CVE-2026-25640"
severity: "HIGH"
cvss: 7.1
epss: "32%"
vendor: "Pydantic"
kev: false
exploited: false
published: "2026-02-06 20:16:11"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T01:53:15+02:00"
---

# CVE-2026-25640

> 7.1 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Erforderlich | good |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 5ab6940f7f0231dc1fc62ab16dea35de018ceebc (Commit)

## Referenzen

- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-25640) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_