PYSEC-2026-1612 Synapse's invalid device keys degrade federation functionality

Impact Lack of validation for device keys in Synapse before 1.138.3 and in Synapse 1.139.0 allow an attacker registered on the victim homeserver to degrade federation functionality, unpredictably breaking outbound federation to other homeservers. Patches Patched in Synapse 1.138.3, 1.138.4,...

CVE-2026-42553

Cinny is a Matrix client. Prior to 4.10.3, A remote authenticated attacker who shares a room with a victim and has permissions to create room emotes for example in a DM can cause the victim's client to send their Matrix access token to an attacker-controlled server. This occurs when the victim...

GHSA-WFQ4-36M3-9G42 Matrix Rust SDK: Sender-binding gaps in to-device and room-key attribution

Impact The matrix-sdk-crypto crate before 0.16.1 is missing a check for the sender's user ID when decrypting an Olm-encrypted to-device message containing the senderdevicekeys property. This could be exploited to spoof the sender of an encrypted to-device message, but only if the attacker collude...

RUSTSEC-2026-0158 Incomplete message edit validation in matrix-sdk-ui

The message edit validation logic in the matrix-sdk-ui crate before 0.16.1 is missing a check: when replacing an encrypted event, the replacement event itself is not required to be encrypted. This enables a malicious homeserver administrator or an actor with equivalent power to impersonate or spo...

RUSTSEC-2026-0159 Sender-binding gaps in to-device messages

The matrix-sdk-crypto crate before 0.16.1 is missing a check for the sender's user ID when decrypting an Olm-encrypted to-device message containing the senderdevicekeys property. This could be exploited to spoof the sender of an encrypted to-device message, but only if the attacker colludes with ...

PT-2026-46305

Name of the Vulnerable Software and Affected Versions matrix-sdk-crypto versions prior to 0.16.1 Description The matrix-sdk-crypto crate fails to verify the sender's user ID during the decryption of Olm-encrypted to-device messages that include the sender device keys property. This flaw allows an...

PYSEC-2026-191

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

PYSEC-2026-194

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This...

DEBIAN-CVE-2026-45076

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This...

PYSEC-2026-191

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

PYSEC-0000-CVE-2026-45076

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This...

DEBIAN-CVE-2026-45078

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

CVE-2026-45076

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This...

CVE-2026-45078

CVE-2026-45078 — Synapse CPU starvation (Denial of Service) Affected: Synapse (open source Matrix homeserver) before version 1.152.1. Issue: Local authenticated users can cause CPU starvation among concurrent requests, leading to other requests failing and denial of service for other users. Impac...

CVE-2026-45078

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

CVE-2026-45078

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

EUVD-2026-32935

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

PT-2026-45981

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1...

CVE-2026-42553 Cinny: Access token disclosure via invalidated emoji pack avatar URL in service worker

Cinny is a Matrix client. Prior to 4.10.3, A remote authenticated attacker who shares a room with a victim and has permissions to create room emotes for example in a DM can cause the victim's client to send their Matrix access token to an attacker-controlled server. This occurs when the victim...

CVE-2026-42553 Cinny: Access token disclosure via invalidated emoji pack avatar URL in service worker

Cinny is a Matrix client. Prior to 4.10.3, A remote authenticated attacker who shares a room with a victim and has permissions to create room emotes for example in a DM can cause the victim's client to send their Matrix access token to an attacker-controlled server. This occurs when the victim...