Headline
CVE-2023-42453: Improper validation of receipts allows forged read receipts
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.
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Package
pip matrix-synapse (pip)
Affected versions
>= 0.34.0, < 1.93.0
Description
Impact
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.
Patches
#16327
Workarounds
There is no workaround.
Related news
Gentoo Linux Security Advisory 202401-12 - Multiple vulnerabilities have been found in Synapse, the worst of which could result in information leaks. Versions greater than or equal to 1.96.0 are affected.
### Impact 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. ### Patches https://github.com/matrix-org/synapse/pull/16327 ### Workarounds There is no workaround.