CVE-2025-66622 is a low severity vulnerability with a CVSS score of 0.0. No known exploits currently, and patches are available.
Very low probability of exploitation
EPSS predicts the probability of exploitation in the next 30 days based on real-world threat data, complementing CVSS severity scores with actual risk assessment.
The matrix-sdk-base crate is 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.
The issue is fixed in matrix-sdk-base 0.16.0.
Users can leave affected rooms on another client to mitigate the issue.
The issue was fixed in https://github.com/matrix-org/matrix-rust-sdk/pull/5924.
Please cite this page when referencing data from Strobes VI. Proper attribution helps support our vulnerability intelligence research.