CVE-2018-12291

HIGHNVD 7.5

7.5

The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.

CVSS v3: 7.5
EG Score: —
EPSS: 53.4%
KEV: Not listed

Published

June 13, 2018

Last Modified

November 21, 2024

References (4)

cve@mitrehttps://github.com/matrix-org/synapse/pull/3371
cve@mitrehttps://github.com/matrix-org/synapse/releases/tag/v0.31.1
af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/synapse/pull/3371
af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/synapse/releases/tag/v0.31.1

Affected Packages

(1 across 1 ecosystem)

PyPI(1)

Package	Vulnerable range	Fixed in	Dependents
matrix-synapse	—	0.31.1	—

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-2018-12291?

CVE-2018-12291 is a high vulnerability published on June 13, 2018. The ongetmissingevents function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the getmissing_events federation API where event visibility rules were not applied correctly.

When was CVE-2018-12291 disclosed?

CVE-2018-12291 was first published in the National Vulnerability Database on June 13, 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-2018-12291 actively exploited?

CVE-2018-12291 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 53.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2018-12291?

CVE-2018-12291 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2018-12291?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-12291, 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-2018-12291

📅 Published

🔄 Last Modified

🔗 References (4)