python-matrix-nio — security advisory
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
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"
}