What’s Vulnerable › Vulnerabilities

CVE-2018-12423

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-06-14 · updated 2026-06-17

Description

In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.

Affected products

• matrix-org synapse: before 0.31.2 — fixed in 0.31.2

How to fix

Upgrade to a fixed version: matrix-org synapse 0.31.2. Check the vendor advisory for mitigations.

References

• https://bugs.debian.org/901549
• https://github.com/matrix-org/matrix-doc/issues/1304
• https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/
• https://bugs.debian.org/901549
• https://github.com/matrix-org/matrix-doc/issues/1304
• https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/

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