CVE-2025-66622

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

Published Dec 9, 2025 CVSS 4.0 · 1.3 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-jj6p-3m75-g2p3 matrix-sdk-base denial of service via custom m.room.join_rules event values
History
Type Values Removed Values Added
First Time appeared Matrix
Matrix matrix-rust-sdk
CPEs cpe:2.3:a:matrix:matrix-rust-sdk:*:*:*:*:*:*:*:*
Vendors & Products Matrix
Matrix matrix-rust-sdk
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Matrix-org
Matrix-org matrix-rust-sdk
Vendors & Products Matrix-org
Matrix-org matrix-rust-sdk
Type Values Removed Values Added
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.
Title matrix-sdk-base is vulnerable to DoS via custom m.room.join_rules event values
Weaknesses CWE-755
References
Metrics cvssV4_0

{'score': 1.3, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Dec 9, 2025, 4:02 PM
Reserved
Dec 5, 2025, 3:18 PM
Status
Analyzed
Published
Dec 9, 2025, 4:18 PM
Modified
Oct 7, 2026, 8:10 PM