CVE-2026-82639

NextChat versions from 2.15.8 through 2.16.1 contain an improper URL validation vulnerability in the proxy endpoint that allows attackers to obtain the server's OpenAI API key. The x-base-url header is validated using substring matching instead of hostname parsing, allowing any URL containing 'api.openai.com' to pass validation and receive the server's credentials in the Authorization header.

  • Published Aug 30, 2026
  • CVSS 8.7 high
  • 0.5% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-82639 at the National Vulnerability Database