CVE-2023-42453

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.

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.

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.

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.

These are all security issues fixed in the matrix-synapse-1.93.0-1.1 package on the GA media of openSUSE Tumbleweed.

It was discovered that Synapse network policies could be bypassed via specially crafted URLs. An attacker could possibly use this issue to bypass authentication mechanisms. (CVE-2023-32683)

It was discovered that Synapse exposed cached device information. An attacker could possibly use this issue to gain access to sensitive information. (CVE-2023-43796)

It was discovered that Synapse could be tricked into rejecting state changes in rooms. An attacker could possibly use this issue to cause Synapse to stop functioning properly, resulting in a denial of service. This issue was only fixed in Ubuntu 20.04 LTS and Ubuntu 22.04 LTS. (CVE-2022-39374)

It was discovered that Synapse stored user credentials in a server's database temporarily. An attacker could possibly use this issue to gain access to sensitive information. This issue was only fixed in Ubuntu 22.04 LTS. (CVE-2023-41335)

It was discovered that Synapse could incorrectly respond to server authorization events. An attacker could possibly use this issue to bypass authentication mechanisms. This issue was only fixed in Ubuntu 22.04 LTS. (CVE-2022-39335)

It was discovered that Synapse could be manipulated to mark messages as read when they had not been viewed. An attacker could possibly use this issue to perform repudiation-based attacks. This issue was only fixed in Ubuntu 22.04 LTS. (CVE-2023-42453)

It was discovered that Synapse had several memory-related issues. An attacker could possibly use this issue to cause Synapse to crash, resulting in a denial of service. This issue was only fixed in Ubuntu 22.04 LTS. (CVE-2024-31208)

It was discovered that Synapse could run external tools due to a unchecked thumbnail rendering routine. An attacker could possibly use this issue to cause Synapse to crash, resulting in a denial of service, or execute arbitrary code. This issue was only fixed in Ubuntu 22.04 LTS. (CVE-2024-53863)