Vulnerability-Lookup

GHSA-VC32-4GWF-77XP

Vulnerability from github – Published: 2026-10-15 20:14 – Updated: 2026-10-15 20:14

Summary

Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools

Details

Summary

An OTP-enabled authenticated user who cannot use the HTTP configuration mutation endpoints without a valid secure session can still mutate Nginx configuration through /mcp and /mcp_message using only ordinary authentication.

Details

The HTTP configuration mutation surface is explicitly grouped behind middleware.RequireSecureSession(). By contrast, the MCP endpoints are exposed with only middleware.AuthRequired(). The MCP server exposes configuration mutation tools including nginx_config_add and nginx_config_modify, so OTP-enabled users gain an alternate path around the intended step-up requirement.

Relevant code paths: - api/config/router.go - internal/middleware/secure_session.go - mcp/router.go - mcp/config/config_add.go - mcp/config/config_modify.go

This is a security-control bypass rather than a missing feature. The product already established that OTP-enabled users should complete a secure session before high-impact configuration mutations are accepted on the HTTP path.

PoC

I verified this locally in an isolated environment with a temporary end-to-end harness that exercised the real /mcp and /mcp_message routes.

What the executed test did: 1. Created a temporary config directory and configured Nginx control commands to harmless local values (true) to avoid touching the host. 2. Created a real OTP-enabled user in a temporary SQLite database. 3. Generated a real JWT for that OTP-enabled user. 4. Started a local test server exposing the real /mcp and /mcp_message routes. 5. Opened an authenticated SSE connection to /mcp with the JWT and no X-Secure-Session-ID. 6. Initialized the MCP session over /mcp_message. 7. Called the real nginx_config_add tool over /mcp_message. 8. Verified that the tool succeeded and created mcp-bypass.conf in the managed config directory without any secure-session step-up.

Observed result from the actual local verification: - The MCP session initialized successfully without any X-Secure-Session-ID. - The config file was written through the MCP tool path using only JWT authentication.

Impact

OTP-enabled accounts lose the intended step-up protection for high-impact Nginx configuration changes when MCP is enabled. A user who should be blocked until re-authenticating can still create or modify configuration files and trigger reload behavior through MCP.

Severity

8.1 (High)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/0xJacky/Nginx-UI"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.9.10-0.20260703131214-23d1934099b0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-84360"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-288"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-15T20:14:10Z",
    "nvd_published_at": "2026-10-12T21:17:22Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nAn OTP-enabled authenticated user who cannot use the HTTP configuration mutation endpoints without a valid secure session can still mutate Nginx configuration through `/mcp` and `/mcp_message` using only ordinary authentication.\n\n### Details\nThe HTTP configuration mutation surface is explicitly grouped behind `middleware.RequireSecureSession()`. By contrast, the MCP endpoints are exposed with only `middleware.AuthRequired()`. The MCP server exposes configuration mutation tools including `nginx_config_add` and `nginx_config_modify`, so OTP-enabled users gain an alternate path around the intended step-up requirement.\n\nRelevant code paths:\n- [api/config/router.go](/home/kali/Desktop/bounty/nginx-ui/api/config/router.go:14)\n- [internal/middleware/secure_session.go](/home/kali/Desktop/bounty/nginx-ui/internal/middleware/secure_session.go:52)\n- [mcp/router.go](/home/kali/Desktop/bounty/nginx-ui/mcp/router.go:9)\n- [mcp/config/config_add.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_add.go:34)\n- [mcp/config/config_modify.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_modify.go:55)\n\nThis is a security-control bypass rather than a missing feature. The product already established that OTP-enabled users should complete a secure session before high-impact configuration mutations are accepted on the HTTP path.\n\n### PoC\nI verified this locally in an isolated environment with a temporary end-to-end harness that exercised the real `/mcp` and `/mcp_message` routes.\n\nWhat the executed test did:\n1. Created a temporary config directory and configured Nginx control commands to harmless local values (`true`) to avoid touching the host.\n2. Created a real OTP-enabled user in a temporary SQLite database.\n3. Generated a real JWT for that OTP-enabled user.\n4. Started a local test server exposing the real `/mcp` and `/mcp_message` routes.\n5. Opened an authenticated SSE connection to `/mcp` with the JWT and no `X-Secure-Session-ID`.\n6. Initialized the MCP session over `/mcp_message`.\n7. Called the real `nginx_config_add` tool over `/mcp_message`.\n8. Verified that the tool succeeded and created `mcp-bypass.conf` in the managed config directory without any secure-session step-up.\n\nObserved result from the actual local verification:\n- The MCP session initialized successfully without any `X-Secure-Session-ID`.\n- The config file was written through the MCP tool path using only JWT authentication.\n\n### Impact\nOTP-enabled accounts lose the intended step-up protection for high-impact Nginx configuration changes when MCP is enabled. A user who should be blocked until re-authenticating can still create or modify configuration files and trigger reload behavior through MCP.",
  "id": "GHSA-vc32-4gwf-77xp",
  "modified": "2026-10-15T20:14:10Z",
  "published": "2026-10-15T20:14:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-vc32-4gwf-77xp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84360"
    },
    {
      "type": "WEB",
      "url": "https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/0xJacky/nginx-ui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools"
}

CVE-2026-84360 (GCVE-0-2026-84360)

Vulnerability from cvelistv5 – Published: 2026-10-12 21:08 – Updated: 2026-10-13 14:00

Title

Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools

Summary

Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.

Severity

8.1 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-13 14:00 UTC

CWE

CWE-288 - Authentication Bypass Using an Alternate Path or Channel

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7619 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/0xJacky/nginx-ui/security/advi…	x_refsource_CONFIRM
https://github.com/0xJacky/nginx-ui/commit/23d193…	x_refsource_MISC
https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
0xJacky	nginx-ui	Affected: < 2.4.1

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-84360",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-13T14:00:07.727918Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-13T14:00:35.965Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-vc32-4gwf-77xp"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nginx-ui",
          "vendor": "0xJacky",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.4.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-288",
              "description": "CWE-288: Authentication Bypass Using an Alternate Path or Channel",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-12T21:08:04.687Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-vc32-4gwf-77xp",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-vc32-4gwf-77xp"
        },
        {
          "name": "https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2"
        },
        {
          "name": "https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1"
        }
      ],
      "source": {
        "advisory": "GHSA-vc32-4gwf-77xp",
        "discovery": "UNKNOWN"
      },
      "title": "Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-84360",
    "datePublished": "2026-10-12T21:08:04.687Z",
    "dateReserved": "2026-09-01T16:27:58.128Z",
    "dateUpdated": "2026-10-13T14:00:35.965Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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GHSA-VC32-4GWF-77XP

Summary

Details

PoC

Impact

CVE-2026-84360 (GCVE-0-2026-84360)

Tags

Sightings

Nomenclature

Vulnerability timeline

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