CVE-2023-38691

{
  "id": "CVE-2023-38691",
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          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
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          "version": "2.0.3",
          "timestamp": "2024-10-07T13:01:18.486033Z"
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        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
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        "impactScore": 1.4,
        "exploitabilityScore": 3.1
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
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          "availabilityImpact": "NONE",
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          "confidentialityImpact": "HIGH"
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        "impactScore": 3.6,
        "exploitabilityScore": 2.8
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  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "matrix-org",
          "product": "matrix-appservice-bridge",
          "versions": [
            {
              "status": "affected",
              "version": ">= 4.0.0, < 8.1.2"
            },
            {
              "status": "affected",
              "version": "= 9.0.0"
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  "published": "2023-08-04T17:15:11.063",
  "references": [
    {
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552",
      "tags": [
        "Patch"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x",
      "tags": [
        "Third Party Advisory"
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    {
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552",
      "tags": [
        "Patch"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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    {
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x",
      "tags": [
        "Third Party Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
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      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
          "value": "CWE-287"
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  "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'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."
    }
  ],
  "lastModified": "2026-06-17T06:10:57.813",
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      "nodes": [
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