Is CVE-2023-43796 in the CISA KEV catalog?

No. CVE-2023-43796 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2023-43796?

CVE-2023-43796 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2023-43796?

CVE-2023-43796 has an EPSS score of 0.90% (55th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2023-43796?

Upgrade matrix-synapse on debian unstable to 1.95.1-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2023-43796

MEDIUM

5.3

CVSS v3

NVD

Description

Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1, cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround, the `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.

CWE-200Information Exposure

How to fix

Remediation Available

matrix-synapseDebian

Fixed in:1.95.1-1CVE-2023-43796

matrix-synapseUbuntu

Fixed in:0.24.0+dfsg-1ubuntu0.1~esm4USN-7444-1

Fixed in:1.11.0-1ubuntu0.1~esm2USN-7444-1

Fixed in:1.53.0-1ubuntu0.1~esm2USN-7444-1

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 ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

0.90%probability of exploitation in 30 days

55thpercentile

Moderate risk: more likely to be exploited than 55% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Mailing List2

Other references1

security.gentoo.org

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 2025-02-13.