Is CVE-2021-39164 in the CISA KEV catalog?

No. CVE-2021-39164 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-39164?

CVE-2021-39164 has a CVSS v3 base score of 3.1 (LOW).

What is the EPSS score for CVE-2021-39164?

CVE-2021-39164 has an EPSS score of 1.46% (70th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-39164?

Upgrade matrix-synapse on debian unstable to 1.41.1-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-39164

LOWEPSS 70th pctl

3.1

CVSS v3

NVD

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.

CWE-200Information Exposure CWE-863Incorrect Authorization

How to fix

Remediation Available

matrix-synapseDebian

Fixed in:1.41.1-1CVE-2021-39164

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

1.46%probability of exploitation in 30 days

70thpercentile

Elevated risk: more likely to be exploited than 70% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory2

Other references2

Related Vulnerabilities

Other CWE-200 (Information Exposure) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-24919	High	8.6	100%	KEV + Ransom	-
CVE-2020-14181	Medium	5.3	100%	-	Fix
CVE-2021-34429	Medium	5.3	99%	-	Fix
CVE-2018-11409	Medium	5.3	98%	-	-
CVE-2021-41277	Critical	10.0	97%	KEV	-
CVE-2016-2183	High	7.5	96%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.