CVE-2026-82639CWE-20

CVE-2026-82639

High · published August 30, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
42.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
EPSS
0.00508 · 42.5th percentile
Weakness
CWE-20 · Improper Input Validation
Published
2026-08-30T18:17Z
References (5)
https://github.com/ChatGPTNextWeb/NextChat · [email protected]https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts · [email protected]https://github.com/ChatGPTNextWeb/NextChat/issues/6814 · [email protected]https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure · [email protected]https://github.com/ChatGPTNextWeb/NextChat/issues/6814 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 01 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 30 AUG 13:23Z
    NextChat 2.15.8 through 2.16.1 OpenAI API Key Disclosure
    cvelistv5