VulnerabilityModified
CVE-2018-12423
In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.
HIGH 7.5EPSS 1.81%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.81%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS
- 1.81% probability · 79th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- matrix/synapse
- Source
- cve@mitre.org
EPSS 1.8% since 28 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugs.debian.org/901549Mailing List, Third Party Advisory
- https://github.com/matrix-org/matrix-doc/issues/1304Third Party Advisory
- https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/Vendor Advisory
- https://bugs.debian.org/901549Mailing List, Third Party Advisory
- https://github.com/matrix-org/matrix-doc/issues/1304Third Party Advisory
- https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.