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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00298.

Exploitation poc

Automatable yes

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
ChatGPTNextWeb NextChat unaffected
Version Status Constraints
2.15.8 affected ≤ 2.16.1

No data.

No data.

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Vendors Products
Chatgptnextweb Subscribe
Nextchat Subscribe
Nextchat Subscribe
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Project Subscriptions

Vendors Products
Chatgptnextweb Subscribe
Nextchat Subscribe
Nextchat Subscribe
Nextchat Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/ChatGPTNextWeb/NextChat cve-icon cve-icon
https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts cve-icon cve-icon
https://github.com/ChatGPTNextWeb/NextChat/issues/6814 cve-icon cve-icon cve-icon
https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure cve-icon cve-icon
History

Mon, 31 Aug 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Sun, 30 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Chatgptnextweb
Chatgptnextweb nextchat
Vendors & Products Chatgptnextweb
Chatgptnextweb nextchat

Sun, 30 Aug 2026 13:30:00 +0000

Type Values Removed Values Added
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.
Title NextChat 2.15.8 through 2.16.1 OpenAI API Key Disclosure
First Time appeared Nextchat
Nextchat nextchat
Weaknesses CWE-20
CPEs cpe:2.3:a:nextchat:nextchat:*:*:*:*:*:*:*:*
Vendors & Products Nextchat
Nextchat nextchat
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 8.7, 'vector': '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-31T16:51:17.973Z

Reserved: 2026-08-30T13:06:02.366Z

Link: CVE-2026-82639

cve-icon Vulnrichment

Updated: 2026-08-31T16:50:36.617Z

cve-icon NVD

Status : Deferred

Published: 2026-08-30T14:17:03.750

Modified: 2026-09-10T15:53:23.707

Link: CVE-2026-82639

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-30T17:15:04Z

Weaknesses