Vulnerability · Published Dec 9, 2025 · Assigned by GitHub_M

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

Low 1.3

In plain English

A low-severity security flaw in matrix-rust-sdk from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).

Severity (CVSS 4.0)1.3Low

Exploit odds (30 days)0.4%top 64.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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 products (as reported)

Vendor	Product	Versions
matrix-org	matrix-rust-sdk	< 0.16.0

Weakness: CWE-755 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

References

https://github.com/matrix-org/matrix-rust-sdk/security/advisories/GHSA-jj6p-3m75-g2p3 x_refsource_CONFIRM
https://github.com/matrix-org/matrix-rust-sdk/pull/5924 x_refsource_MISC
https://github.com/matrix-org/matrix-rust-sdk/commit/4ea0418abefab2aa93f8851a4d39c723e703e6b0 x_refsource_MISC
https://rustsec.org/advisories/RUSTSEC-2025-0135.html x_refsource_MISC