CVE-2018-12423

HIGHNVD 7.5

7.5

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

CVSS v3: 7.5
EG Score: —
EPSS: 50.7%
KEV: Not listed

Published

June 14, 2018

Last Modified

November 21, 2024

References (6)

cve@mitrehttps://bugs.debian.org/901549
cve@mitrehttps://github.com/matrix-org/matrix-doc/issues/1304
cve@mitrehttps://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/
af854a3a-2127-422b-91ae-364da2661108https://bugs.debian.org/901549
af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/matrix-doc/issues/1304
af854a3a-2127-422b-91ae-364da2661108https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/

Affected Packages

(1 across 1 ecosystem)

PyPI(1)

Package	Vulnerable range	Fixed in	Dependents
matrix-synapse	—	0.31.2	—

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:38 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 04:46 UTCOSV refresh

Frequently asked(5)

What is CVE-2018-12423?

CVE-2018-12423 is a high vulnerability published on June 14, 2018. In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.

When was CVE-2018-12423 disclosed?

CVE-2018-12423 was first published in the National Vulnerability Database on June 14, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2018-12423 actively exploited?

CVE-2018-12423 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 50.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2018-12423?

CVE-2018-12423 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2018-12423?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-12423, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2018-12423

📅 Published

🔄 Last Modified

🔗 References (6)