---
id: CVE-2026-82639
title: >-
  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
summary: >-
  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 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-20
published: '2026-08-30'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T15:53:23.707'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82639'
references:
  - url: 'https://github.com/ChatGPTNextWeb/NextChat'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ChatGPTNextWeb/NextChat/issues/6814'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure
    label: disclosure@vulncheck.com
  - url: 'https://github.com/ChatGPTNextWeb/NextChat/issues/6814'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00508
epssPercentile: 0.40915
ingestedAt: '2026-08-30T23:59:28.088Z'
vendor: ChatGPTNextWeb
product: NextChat
affected:
  - NextChat >= 2.15.8 <= 2.16.1
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-08-31T16:51:12.882744Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.