FKIE_CVE-2023-38691

Vulnerability from fkie_nvd - Published: 2023-08-04 17:15 - Updated: 2026-06-17 06:10
Severity
5.0 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Summary
matrix-appservice-bridge provides an API for setting up bridges. Starting in version 4.0.0 and prior to versions 8.1.2 and 9.0.1, a malicious Matrix server can use a foreign user's MXID in an OpenID exchange, allowing a bad actor to impersonate users when using the provisioning API. The library does not check that the servername part of the `sub` parameter (containing the user's *claimed* MXID) is the the same as the servername we are talking to. A malicious actor could spin up a server on any given domain, respond with a `sub` parameter according to the user they want to act as and use the resulting token to perform provisioning requests. Versions 8.1.2 and 9.0.1 contain a patch. As a workaround, disable the provisioning API.
References
security-advisories@github.comhttps://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552Patch
security-advisories@github.comhttps://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5xThird Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552Patch
af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5xThird Party Advisory
Impacted products
Vendor Product Version
matrix matrix-appservice-bridge *
matrix matrix-appservice-bridge 9.0.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "matrix-appservice-bridge",
          "vendor": "matrix-org",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 8.1.2"
            },
            {
              "status": "affected",
              "version": "= 9.0.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:matrix:matrix-appservice-bridge:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "DC6F33A1-2DFE-4F73-8C67-45C4782AC792",
              "versionEndExcluding": "8.1.2",
              "versionStartIncluding": "4.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:matrix:matrix-appservice-bridge:9.0.0:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "40415786-C971-407F-9E51-9C5203B4F2CB",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "matrix-appservice-bridge provides an API for setting up bridges. Starting in version 4.0.0 and prior to versions 8.1.2 and 9.0.1, a malicious Matrix server can use a foreign user\u0027s MXID in an OpenID exchange, allowing a bad actor to impersonate users when using the provisioning API. The library does not check that the servername part of the `sub` parameter (containing the user\u0027s *claimed* MXID) is the the same as the servername we are talking to. A malicious actor could spin up a server on any given domain, respond with a `sub` parameter according to the user they want to act as and use the resulting token to perform provisioning requests. Versions 8.1.2 and 9.0.1 contain a patch. As a workaround, disable the provisioning API."
    }
  ],
  "id": "CVE-2023-38691",
  "lastModified": "2026-06-17T06:10:57.813",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.0,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2023-38691",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2024-10-07T13:01:18.486033Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2023-08-04T17:15:11.063",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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