CVE-2023-42453
matrix-synapse vulnerable to improper validation of receipts allows forged read receipts
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.
How to fix CVE-2023-42453
To remediate CVE-2023-42453, upgrade the affected package to a fixed version below.
- —upgrade to 1.93.0-1 or later
- —upgrade to 1.93.0 or later
- —upgrade to 1.93.0 or later
Is CVE-2023-42453 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.93.0-1
- >= 0.34.0, < 1.93.0
- >= 1.34.0, < 1.93.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | LOW3.1 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |