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python-matrix-nio — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2022-39254

matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue.

Products
python-matrix-nio
Affected versions
Not specified
Fixed versions
0.20.0-1
CVEs
CVE-2022-39254
Confirmed fixed CVEs
Not specified
Updated in this feed
30 Oct 2026, 14:52 UTC · Revision 1

Source evidence

DEBIAN-CVE-2022-39254

core-osv · Original source

Published 29 Sept 2022, 15:15 UTC

matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue.

osv:DEBIAN-CVE-2022-39254

python-matrix-nio

Fixed versions: 0.20.0-1

python-matrix-nio

Fixed versions: 0.20.0-1

python-matrix-nio

Fixed versions: 0.20.0-1

Complete source record
{
  "id": "0dafaba463e68293785ce9671f840fdf7a628b9975e35714bf1b834d91396f0b",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2022-39254",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2022-39254",
    "summary": "matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue.",
    "evidence": "osv:DEBIAN-CVE-2022-39254",
    "products": [
      {
        "name": {
          "value": "python-matrix-nio",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.20.0-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "python-matrix-nio",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.20.0-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "python-matrix-nio",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.20.0-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2022-39254",
      "aliases": [
        "DEBIAN-CVE-2022-39254"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.20.0-1"
                }
              ]
            }
          ],
          "package": {
            "name": "python-matrix-nio",
            "purl": "pkg:deb/debian/python-matrix-nio?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2022-39254.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.20.0-1"
                }
              ]
            }
          ],
          "package": {
            "name": "python-matrix-nio",
            "purl": "pkg:deb/debian/python-matrix-nio?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2022-39254.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.20.0-1"
                }
              ]
            }
          ],
          "package": {
            "name": "python-matrix-nio",
            "purl": "pkg:deb/debian/python-matrix-nio?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2022-39254.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-15T08:02:32.008947965Z",
      "provider": "osv",
      "upstream": [
        "CVE-2022-39254"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2022-39254"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2022-39254",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 323544,
  "published_at": "2022-09-29T15:15:10.513+00:00"
}