matrix-sdk-base is vulnerable to DoS via custom m.room.join_rules event values
Priority LOW 14CWE-755Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00413 35th percentileScored 2026-11-07
Fix Fixed matrix-rust-sdk (matrix-org): 0.16.0matrix-sdk-base (crates.io): 0.16.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| matrix-org | matrix-rust-sdk | before 0.16.0 | 0.16.0 | Patch available | CNA |
| — | matrix-sdk-base (crates.io) | before 0.16.0 | 0.16.0 | Patch available | GHSA-jj6p-3m75-g2p3 |
- matrix-rust-sdk Vendormatrix-org Affected before 0.16.0 Fixed in 0.16.0 Patch available CNA
- matrix-sdk-base (crates.io) Vendor— Affected before 0.16.0 Fixed in 0.16.0 Patch available GHSA-jj6p-3m75-g2p3
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:matrix-rust-sdk:*:*:*:*:*:*:*:* | before 0.16.0 | Vulnerable | matrix-org |
- cpe:2.3:a:matrix:matrix-rust-sdk:*:*:*:*:*:*:*:* Versions before 0.16.0 Vulnerable ·matrix-org
Remediation
- Fix · CNA matrix-rust-sdk (matrix-org) Fixed in 0.16.0
- Fix · GHSA-jj6p-3m75-g2p3 matrix-sdk-base (crates.io) Fixed in 0.16.0 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2025-66622
- 2026-10-03 Alias added: GHSA-jj6p-3m75-g2p3
References
Patch 3
Advisory 2
More matrix-org Matrix-rust-sdk vulnerabilities
- TI-2022-18628 When matrix-rust-sdk recieves forwarded room keys, the reciever doesn't check if it requested the key from the forwarder CVSS 3.1HIGH 8.6
Sources
- CVE-2025-66622 · CVE Program
- CVE-2025-66622 · NVD
- FIRST EPSS
- GHSA-jj6p-3m75-g2p3 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-66622 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences