GHSA-x345-32rc-8h85
Vulnerability from github
Published
2021-05-13 20:22
Modified
2024-09-30 20:43
Severity ?
3.7 (Low) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Summary
Denial of service attack via push rule patterns in matrix-synapse
Details

Impact

"Push rules" can specify conditions under which they will match, including event_match, which matches event content against a pattern including wildcards.

Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events.

Patches

The issue is patched by https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c.

Workarounds

A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.

For more information

If you have any questions or comments about this advisory, email us at security@matrix.org.

Show details on source website

To clipboard 

{
   affected: [
      {
         package: {
            ecosystem: "PyPI",
            name: "matrix-synapse",
         },
         ranges: [
            {
               events: [
                  {
                     introduced: "0",
                  },
                  {
                     fixed: "1.33.2",
                  },
               ],
               type: "ECOSYSTEM",
            },
         ],
      },
   ],
   aliases: [
      "CVE-2021-29471",
   ],
   database_specific: {
      cwe_ids: [
         "CWE-331",
         "CWE-400",
      ],
      github_reviewed: true,
      github_reviewed_at: "2021-05-11T17:19:15Z",
      nvd_published_at: "2021-05-11T15:15:00Z",
      severity: "MODERATE",
   },
   details: "### Impact\n\n\"Push rules\" can specify [conditions](https://matrix.org/docs/spec/client_server/r0.6.1#conditions) under which they will match, including `event_match`, which matches event content against a pattern including wildcards.\n\nCertain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events.\n\n### Patches\n\nThe issue is patched by https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c.\n\n### Workarounds\n\nA potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.",
   id: "GHSA-x345-32rc-8h85",
   modified: "2024-09-30T20:43:40Z",
   published: "2021-05-13T20:22:51Z",
   references: [
      {
         type: "WEB",
         url: "https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85",
      },
      {
         type: "ADVISORY",
         url: "https://nvd.nist.gov/vuln/detail/CVE-2021-29471",
      },
      {
         type: "WEB",
         url: "https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c",
      },
      {
         type: "PACKAGE",
         url: "https://github.com/matrix-org/synapse",
      },
      {
         type: "WEB",
         url: "https://github.com/matrix-org/synapse/releases/tag/v1.33.2",
      },
      {
         type: "WEB",
         url: "https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-135.yaml",
      },
      {
         type: "WEB",
         url: "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY",
      },
   ],
   schema_version: "1.4.0",
   severity: [
      {
         score: "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
         type: "CVSS_V3",
      },
      {
         score: "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
         type: "CVSS_V4",
      },
   ],
   summary: "Denial of service attack via push rule patterns in matrix-synapse",
}


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