PT-2026-6789 · Unknown · Pydantic-Ai

Amiteliahu + 2 · Published 2026-02-06 · Updated 2026-02-06 · CVE-2026-25640

Positive Technologies (AI Summary)

CVSS v3.1

7.1

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Pydantic AI versions 1.34.0 through 1.50.9

Description Pydantic AI contains a path traversal issue in its web UI. A crafted URL can be used by an attacker to serve arbitrary JavaScript within the application's context. This allows execution of attacker-controlled code in the victim's browser, potentially leading to theft of chat history and session cookies. The issue arises because the CDN URL is constructed using a non-validated version query parameter from the request URL, enabling path traversal sequences. This vulnerability affects applications utilizing Agent.to web or clai web to serve a chat interface, which may be running locally or on a remote server.

Recommendations Upgrade to version 1.51.0 or later to remove the user-controllable version parameter and prevent the vulnerability.

Exploit

Fix

Path traversal

XSS

Weakness Enumeration

CWE-22

CWE-79

Related Identifiers

CVE-2026-25640

GHSA-WJP5-868J-WQV7

Affected Products

Pydantic-Ai

References · 9

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25640.json · Exploit
• https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-wjp5-868j-wqv7 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-25640 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-wjp5-868j-wqv7 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-25640 · Security Note
• https://github.com/pydantic/pydantic-ai · Note
• https://github.com/pydantic/pydantic-ai/releases/tag/v1.51.0 · Note
• https://twitter.com/CVEnew/status/2019876699769602276 · Twitter Post
• https://t.me/CVEtracker/43962 · Telegram Post