CVE-2025-666221.3LowCWE-755

CVE-2025-66622: matrix-sdk-base is vulnerable to DoS via custom m.room.join_rules event values

matrix-org · matrix-rust-sdk

Affected: matrix-org matrix-rust-sdk · Exploitation: unlikely (under 1%)

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

0.4%probability of exploitation in the next 30 days

39th percentile

050100

Higher than 39% of scored CVEs

1.3LowCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

matrix-sdk-base is the base component to build a Matrix client library. Versions 0.14.1 and prior are unable to handle responses that include custom m.room.join_rules values due to a serialization bug. This can be exploited to cause a denial-of-service condition, if a user is invited to a room with non-standard join rules, the crate's sync process will stall, preventing further processing for all rooms. This is fixed in version 0.16.0.

Affected products1

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

matrix-org · matrix-rust-sdk< 0.16.0

On the Atlas

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

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Handling of Exceptional Conditions · Input Validation and Logic
Vendor: matrix-org
Published: December 2025
Band: Unlikely (under 1%), December 2025

CoverageNo articles yet

No CyberSIXT article names CVE-2025-66622 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.