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High

Security advisory

Type: advisorySources: OSVCVE: CVE-2018-12291

The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2018-12291
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 10:25 UTC · Revision 1

Source evidence

CVE-2018-12291

core-osv · Original source

Published 13 Jun 2018, 14:29 UTC

The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.

osv:CVE-2018-12291
Complete source record
{
  "id": "c1c2e590d8429fd746527a3c6c47aeec1c74c639c60fab1af77379c5eee509a7",
  "url": "https://osv.dev/vulnerability/CVE-2018-12291",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-12291",
    "summary": "The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.",
    "evidence": "osv:CVE-2018-12291",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2018-12291",
      "aliases": [
        "CVE-2018-12291",
        "GHSA-v8wm-g9f2-xjv4",
        "PYSEC-2026-664"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/matrix-org/synapse",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "aefcc0f5e5e3b4ce6020dd895045ddf5f83ba5d9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.31.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "aefcc0f5e5e3b4ce6020dd895045ddf5f83ba5d9"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.31.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.31.0",
            "v0.31.0-rc1",
            "v0.28.0-rc1",
            "v0.25.0-rc1",
            "v0.23.0-rc2",
            "v0.23.0-rc1",
            "v0.18.5",
            "v0.18.4",
            "v0.18.3",
            "v0.18.2",
            "v0.18.1",
            "v0.18.0",
            "v0.17.3",
            "v0.17.2",
            "v0.17.1",
            "v0.17.0",
            "v0.16.1-r1",
            "v0.16.1",
            "v0.16.0",
            "v0.14.0",
            "v0.13.3",
            "v0.13.2",
            "v0.13.1",
            "v0.12.0",
            "v0.11.1",
            "v0.11.0-r2",
            "v0.11.0-r1",
            "v0.11.0",
            "v0.10.0-r2",
            "v0.10.0-r1",
            "v0.10.0",
            "v0.9.3",
            "v0.9.2-r2",
            "v0.9.2-r1",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0-r5",
            "v0.9.0-r4",
            "v0.9.0-r3",
            "v0.9.0-r2",
            "v0.9.0-r1",
            "v0.9.0",
            "v0.8.1-r4",
            "v0.8.1-r3",
            "v0.8.1-r2",
            "v0.8.1-r1",
            "v0.8.1",
            "v0.8.0",
            "v0.7.1-r4",
            "v0.7.1-r3",
            "v0.7.1-r2",
            "v0.7.1-r1",
            "v0.7.1",
            "v0.7.0f",
            "v0.7.0e",
            "v0.7.0d",
            "v0.7.0c",
            "v0.7.0b",
            "v0.7.0a",
            "v0.7.0",
            "v0.6.1f",
            "v0.6.1e",
            "v0.6.1d",
            "v0.6.1c",
            "v0.6.1b",
            "v0.6.1a",
            "v0.6.1",
            "v0.6.0b",
            "v0.6.0a",
            "v0.6.0",
            "v0.5.4a",
            "v0.5.4",
            "v0.5.3c",
            "v0.5.3b",
            "v0.5.3a",
            "v0.5.3",
            "v0.5.2",
            "v0.5.1",
            "v0.5.0",
            "v0.4.2",
            "v0.4.1",
            "v0.3.4",
            "v0.3.3",
            "v0.3.0",
            "v0.2.2",
            "v0.2.1a",
            "v0.2.1",
            "v0.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-12291.json"
          }
        }
      ],
      "modified": "2026-10-20T10:50:17.954027865Z",
      "provider": "osv",
      "references": [
        "https://github.com/matrix-org/synapse/releases/tag/v0.31.1",
        "https://github.com/matrix-org/synapse/pull/3371"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-12291",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 381503,
  "published_at": "2018-06-13T14:29:00.273+00:00"
}