Medium severity · published Dec 3, 2024
CVE-2024-53867
Synapse Matrix has a partial room state leak via Sliding Sync
4.3
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SY
synapse · element-hq
>= 1.113.0rc1, < 1.120.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-53867
CVE.org
https://www.cve.org/CVERecord?id=CVE-2024-53867
github.com
https://github.com/element-hq/synapse/security/advisories/GHSA-56w4-5538-8v8h
github.com
https://github.com/matrix-org/matrix-spec-proposals/pull/4186
More from synapse
9.1
CVE-2024-53863
Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders
7.5
CVE-2025-30355
Synapse vulnerable to federation denial of service via malformed events
7.5
CVE-2024-37302
Synapse denial of service through media disk space consumption
7.5
CVE-2024-52805
Synapse allows unsupported content types to lead to memory exhaustion
5.5
CVE-2026-45078
Synapse CPU starvation (Denial of Service)