CVE-2024-53867
Synapse Matrix has a partial room state leak via Sliding Sync
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Synapse Matrix has a partial room state leak via Sliding Sync
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.
- Record
CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-497
- Updated
- 2026-11-02
EUVDEUVD-2024-3430
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.
- Record
EUVD-2024-3430- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-56w4-5538-8v8h
Synapse Matrix has a partial room state leak via Sliding Sync
Impact
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.
Patches
Synapse version 1.120.1 fixes the problem.
Workarounds
Disable Sliding Sync.
References
https://github.com/matrix-org/matrix-spec-proposals/pull/4186 https://github.com/element-hq/synapse/blob/d80cd57c54427687afcb48740d99219c88a0fff1/synapse/config/experimental.py#L341-L344
For more information
If you have any questions or comments about this advisory, please email us at security at element.io.
- Record
GHSA-56w4-5538-8v8h- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-497
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-497
- Updated
- 2026-11-02
OSVALPINE-CVE-2024-53867
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.
- Record
ALPINE-CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
OSV
Synapse Matrix has a partial room state leak via Sliding Sync
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.
- Record
CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-497
- Updated
- 2026-11-02
Show 5 moreShow less
OSVDEBIAN-CVE-2024-53867
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.
- Record
DEBIAN-CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVGHSA-56w4-5538-8v8h
Synapse Matrix has a partial room state leak via Sliding Sync
Impact
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.
Patches
Synapse version 1.120.1 fixes the problem.
Workarounds
Disable Sliding Sync.
References
https://github.com/matrix-org/matrix-spec-proposals/pull/4186 https://github.com/element-hq/synapse/blob/d80cd57c54427687afcb48740d99219c88a0fff1/synapse/config/experimental.py#L341-L344
For more information
If you have any questions or comments about this advisory, please email us at security at element.io.
- Record
GHSA-56w4-5538-8v8h- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-497
- Updated
- 2026-11-02
OSVPYSEC-2026-1610
Synapse Matrix has a partial room state leak via Sliding Sync
Impact
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.
Patches
Synapse version 1.120.1 fixes the problem.
Workarounds
Disable Sliding Sync.
References
https://github.com/matrix-org/matrix-spec-proposals/pull/4186 https://github.com/element-hq/synapse/blob/d80cd57c54427687afcb48740d99219c88a0fff1/synapse/config/experimental.py#L341-L344
For more information
If you have any questions or comments about this advisory, please email us at security at element.io.
- Record
PYSEC-2026-1610- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2024-53867
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.
- Record
UBUNTU-CVE-2024-53867- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVopenSUSE-SU-2024:14541-1 No score
matrix-synapse-1.120.2-1.1 on GA media
These are all security issues fixed in the matrix-synapse-1.120.2-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:14541-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
matrix-synapsePyPI |
1.113.0rc1 up to 1.120.1 | 1.120.1 |
synapseAlpine:v3.20 |
before 1.120.1 | 1.120.1 |
synapseAlpine:v3.21 |
before 1.120.2-r0 | 1.120.2-r0 |
synapseAlpine:v3.22 |
before 1.120.2-r0 | 1.120.2-r0 |
synapseAlpine:v3.23 |
before 1.120.2-r0 | 1.120.2-r0 |
synapseAlpine:v3.24 |
before 1.120.2-r0 | 1.120.2-r0 |
matrix-synapsePyPI |
1.113.0rc1 up to 1.120.1, plus listed versions 1.113.01.114.01.114.0rc11.114.0rc31.115.0 Show 13 moreShow less1.115.0rc11.115.0rc21.116.01.116.0rc11.116.0rc21.117.01.117.0rc11.118.01.118.0rc11.119.01.119.0rc21.120.01.120.0rc1 |
1.120.1 |
matrix-synapseopenSUSE:Tumbleweed From an advisory covering 6 CVEs |
before 1.120.2-1.1 | 1.120.2-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected, aliases, references | OSV | |
| affected | ||
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-53867 is a medium vulnerability (CVSS 4.3) in Element-hq Synapse, published December 3, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.44%, the 38th percentile. Fixed in matrix-synapse 1.120.1.
References
github.com/element-hq/synapse/security/advisories/GHSA-56w4-5538-8v8h
nvd.nist.gov/vuln/detail/CVE-2024-53867
security.alpinelinux.org/vuln/CVE-2024-53867
Show 11 moreShow less
security-tracker.debian.org/tracker/CVE-2024-53867
pypi.org/project/matrix-synapse
ubuntu.com/security/CVE-2024-53867
cve.org/CVERecord?id=CVE-2024-53867
suse.com/security/cve/CVE-2024-37302