Vulnerability-Lookup

CVE-2026-82639 (GCVE-0-2026-82639)

Vulnerability from cvelistv5 – Published: 2026-08-30 13:23 – Updated: 2026-08-31 16:51

Title

NextChat 2.15.8 through 2.16.1 OpenAI API Key Disclosure

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 instead of hostname parsing, allowing any URL containing 'api.openai.com' to pass validation and receive the server's credentials in the Authorization header.

Severity

8.7 (High)


                        
                          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

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-31 16:51 UTC

CWE

CWE-20 - Improper Input Validation

Assigner

VulnCheck mitre root

References

4 references

URL	Tags
https://github.com/ChatGPTNextWeb/NextChat/issues/6814	issue-tracking
https://github.com/ChatGPTNextWeb/NextChat	product
https://github.com/ChatGPTNextWeb/NextChat/blob/v…	technical-description
https://www.vulncheck.com/advisories/nextchat-2.1…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
ChatGPTNextWeb	NextChat	Affected: 2.15.8 , ≤ 2.16.1 (semver) cpe:2.3:a:nextchat:nextchat::::::::

Date Public

2026-07-05 00:00

Credits

George Chen

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-82639

Vulnerability from fkie_nvd - Published: 2026-08-30 14:17 - Updated: 2026-08-30 14:17

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://github.com/ChatGPTNextWeb/NextChat
	disclosure@vulncheck.com	https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts
	disclosure@vulncheck.com	https://github.com/ChatGPTNextWeb/NextChat/issues/6814
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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GHSA-87FX-H8M6-GXWV

Vulnerability from github – Published: 2026-08-30 15:30 – Updated: 2026-08-30 15:30

Details

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

8.7 (High)


                  
                    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

Show details on source website

JSON

To clipboard

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  ],
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      "CWE-20"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-30T14:17:03Z",
    "severity": "HIGH"
  },
  "details": "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\u0027s OpenAI API key. The x-base-url header is validated using substring matching instead of hostname parsing, allowing any URL containing \u0027api.openai.com\u0027 to pass validation and receive the server\u0027s credentials in the Authorization header.",
  "id": "GHSA-87fx-h8m6-gxwv",
  "modified": "2026-08-30T15:30:26Z",
  "published": "2026-08-30T15:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-82639"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ChatGPTNextWeb/NextChat/issues/6814"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ChatGPTNextWeb/NextChat"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ChatGPTNextWeb/NextChat/blob/v2.16.1/app/api/proxy.ts"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nextchat-2.15.8-through-2.16.1-openai-api-key-disclosure"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-82639 (GCVE-0-2026-82639)

FKIE_CVE-2026-82639

GHSA-87FX-H8M6-GXWV

Tags

Sightings

Nomenclature