CVE-2021-39164: fedoraproject fedora
Vulnerability summary
CVE-2021-39164 is a low (CVSS 3.5) vulnerability in fedoraproject fedora. EPSS estimates a 1.45% chance of exploitation in the next 30 days, higher than 72.9% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 31-08-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the membership (list of members, with their display names) of a room if they know the ID of the room. The vulnerability is limited to rooms with `shared` history visibility. Furthermore, the unauthorised user must be using an account on a vulnerable homeserver that is in the room. Server administrators should upgrade to 1.41.1 or later in order to receive the patch. One workaround is available. Administrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the endpoints: `/_matrix/client/r0/rooms/{room_id}/members` with `at` query parameter, and `/_matrix/client/unstable/rooms/{room_id}/members` with `at` query parameter.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · PypiEcosystem advisory · calculated3.1LowCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- OSV · UbuntuEcosystem advisory · calculated3.1LowCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- OSV · DebianEcosystem advisory · calculated3.1LowCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- NVDNIST3.1LowCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
1.45%
Chance of exploitation in the next 30 days
Percentile
73%
Versus all other CVEs
30-day change
-0.01 pp
From 1.46% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
- CWE-863Incorrect AuthorizationThe product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Affected systems
Debian1 product
- matrix-synapse< 1.41.1-1
Fedoraproject1 product
- fedoraEOL34 | 35
Matrix1 product
- synapse< 1.41.1
Matrix-org1 product
- synapse< 1.41.1
PyPI1 product
- matrix-synapse< cb35df940a828bc40b96daed997b5ad4c7842fd3 | < 1.41.1
Ubuntu1 product
- matrix-synapseAll versions (No fix recorded)
6 vendors · 6 products
References
16 links- github.com/matrix-org/synapse/commit/cb35df940aX Refsource MISCWEBFIXREPORTPatchThird Party Advisory
- github.com/matrix-org/synapse/releases/tag/v1.41.1X Refsource MISCWEBREPORTRelease NotesThird Party Advisory
- github.com/matrix-org/synapse/security/advisories/GHSA-3x4c-pq33-4w3qX Refsource CONFIRMWEBAdvisoryREPORTThird Party Advisory