Synapse is an open-source Matrix homeserver. The Sliding Sync feature on Synapse versions between 1.113.0rc1 and 1.120.0 can leak partial room state changes to users no longer in a room. Non-state events, like messages, are unaffected. This vulnerability is fixed in 1.120.1.
CVE ID: CVE-2024-53867
CVSS Base Severity: MEDIUM
CVSS Base Score: 4.3
Vendor: element-hq
Product: synapse
EPSS Score: 0.04% (probability of being exploited)
EPSS Percentile: 11.44% (scored less or equal to compared to others)
EPSS Date: 2025-02-03 (when was this score calculated)