SB20231031124 - Improper access control in Synapse
Published: October 31, 2023 Updated: May 4, 2026
Security Bulletin ID
SB20231031124
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper access control (CVE-ID: CVE-2023-43796)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper access control in cached remote user device information handling when querying device information. A remote attacker can query cached device information of remote users to disclose sensitive information.
This can be used to enumerate remote users known to the homeserver.
Remediation
Install update from vendor's website.