CVE Catalog

CVE-2025-68667

CriticalCVSS 9.9
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.59%

47th percentile - higher than 47% of all known CVEs

Summary

A vulnerability in Conduit and derived Matrix homeservers (continuwuity, Grapevine, tuwunel) allows a remote, unauthenticated attacker to force the server to cryptographically sign arbitrary membership events. Attackers can forge 'leave', 'invite', and 'ban' events, enabling denial of service, removal of room protections, and access to private conversations.

Risk Assessment

The organization may experience chat service unavailability, removal of users (including admins and bots) from rooms, and leakage of confidential information from private or invite-only rooms. In extreme cases, users on the same server can also be banned.

Recommendation

Update Conduit to version 0.10.10 or later, continuwuity to 0.5.0, tuwunel to 1.4.8, and Grapevine to commit 9a50c244. If updating is not possible, block access to the PUT /_matrix/federation/v2/invite/{roomId}/{eventId} endpoint using your reverse proxy.

Related vulnerabilities

Original NVD description (English source)

Conduit is a chat server powered by Matrix. A vulnerability that affects a number of Conduit-derived homeservers allows a remote, unauthenticated attacker to force the target server to cryptographically sign arbitrary membership events. Affected products include Conduit prior to version 0.10.10, continuwuity prior to version 0.5.0, Grapevine prior to commit `9a50c244`, and tuwunel prior to version 1.4.8. The flaw exists because the server fails to validate the origin of a signing request, provided the event's state_key is a valid user ID belonging to the target server. Attackers can forge "leave" events for any user on the target server. This forcibly removes users (including admins and bots) from rooms. This allows denial of service and/or the removal of technical protections for a room (including policy servers, if all users on the policy server are removed). Attackers can forge "invite" events from a victim user to themselves, provided they have an account on a server where there is an account that has the power level to send invites. This allows the attacker to join private or invite-only rooms accessible by the victim, exposing confidential conversation history and room state. Attackers can forge "ban" events from a victim user to any user below the victim user's power level, provided the victim has the power level to issue bans AND the target of the ban resides on the same server as the victim. This allows the attacker to ban anyone in a room who is on the same server as the vulnerable one, however cannot exploit this to ban users on other servers or the victim themself. Conduit fixes the issue in version 0.10.10. continuwuity fixes the issue in commits `7fa4fa98` and `b2bead67`, released in 0.5.0. tuwunel fixes the issue in commit `dc9314de1f8a6e040c5aa331fe52efbe62e6a2c3`, released in 1.4.8. Grapevine fixes the issue in commit `9a50c2448abba6e2b7d79c64243bb438b351616c`. As a workaround, block access to the `PUT /_matrix/federation/v2/invite/{roomId}/{eventId}` endpoint using your reverse proxy.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS