CVE-2026-82639: Improper Input Validation in ChatGPTNextWeb NextChat
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.
CVE-2026-82639: Improper Input Validation in ChatGPTNextWeb NextChat
Description
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.
CVSS v4.0
Score 8.7high
Affected software
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-30T13:06:02.366Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a943230acd9273b4997c70c
Added to database: 08/30/2026, 13:37:52 UTC
Last updated: 08/30/2026, 14:52:14 UTC
Views: 3
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