CVE-2023-42453

unknown
Published 2023-09-26 · Modified 2023-11-08
CVSS v3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS v2
VIR risk

Description

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Users were able to forge read receipts for any event (if they knew the room ID and event ID). Note that the users were not able to view the events, but simply mark it as read. This could be confusing as clients will show the event as read by the user, even if they are not in the room. This issue has been patched in version 1.93.0. Users are advised to upgrade. There are no known workarounds for this issue.

Predictions

Exploit likelihood
30%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2023-42453

OS impact

OSVersionStatusFixed in
debian debianforkyfixed1.93.0-1
debian debiansidfixed1.93.0-1

Package impact

EcosystemPackageVulnerableFixed
python PyPImatrix-synapse>=0.34.0,<1.93.01.93.0
python PyPImatrix-synapse>=1.34.0,<1.93.01.93.0

References

Verify integrity in audit chain (admin only). AS-IS.