CVE-2026-82639
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductNextChat
PublishedAug 30, 2026
First seenAug 30, 2026
Weakness typeCWE-20Improper input validation
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| ChatGPTNextWeb NextChat | 2.15.8 ≤ v ≤ 2.16.1 | — |
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