CVE-2026-56400: open-webui Insufficient Session Expiration

Vulnerability summary

CVE-2026-56400 is a critical (CVSS 9.6) Insufficient Session Expiration vulnerability in open-webui. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 43.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-07-2026
   PublishedVulnerability first disclosed.
2. 15-07-2026
   Last modifiedVulnerability information updated.

Description

open-webui before 0.3.14 contains a cross-origin resource sharing misconfiguration allowing arbitrary origins with allow_origins=* and authenticated requests to the /api/v1/functions endpoint. Attackers can execute arbitrary code on the openwebui instance by crafting malicious cross-site requests from attacker-controlled websites when an admin user visits them.

• CWE-613Insufficient Session ExpirationAccording to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization."