CVE-2021-294713.7LowCWE-400

CVE-2021-29471: Denial of service in Matrix Synapse

matrix-org · synapse

Fixed in 1.33.2 · Affected: matrix-org synapse before 1.33.2 · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

1.6%probability of exploitation in the next 30 days

76th percentile

050100

Higher than 76% of scored CVEs

3.7LowCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.33.2 "Push rules" can specify conditions under which they will match, including `event_match`, which matches event content against a pattern including wildcards. Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events. The issue is patched in version 1.33.2. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

matrix-org · synapse< 1.33.2

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Uncontrolled Resource Consumption · Denial of Service
Vendor: matrix-org
Published: May 2021
Band: Possible (1 to 10%), May 2021

CoverageNo articles yet

No CyberSIXT article names CVE-2021-29471 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.