CVE-2025-62175: 
NixOS vulnerability analysis and mitigation

Mastodon, a free, open-source social network server based on ActivityPub, was found to have a security vulnerability in versions before 4.4.6, 4.3.14, and 4.2.27. The vulnerability (CVE-2025-62175) was discovered and disclosed on October 13, 2025, where disabling or suspending a user account does not disconnect the account from the streaming API. This allows disabled or suspended accounts to continue receiving real-time updates through existing streaming connections and establish new streaming connections, even though they cannot interact with other API endpoints (GitHub Advisory).

The vulnerability has been assigned a CVSS v3.1 score of 4.3 (Moderate) with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N. The issue is related to two Common Weakness Enumerations (CWE): CWE-273 (Improper Check for Dropped Privileges) and CWE-274 (Improper Handling of Insufficient Privileges). The technical nature of the vulnerability involves the streaming API continuing to maintain connections and accept new connections from accounts that have been administratively disabled or suspended (GitHub Advisory).

The vulnerability undermines moderation actions, as administrators expect disabled or suspended accounts to be fully disconnected from the service. Affected accounts can continue to receive messages in their app via the streaming API, despite being unable to interact with other API endpoints. This could significantly impact servers' ability to effectively moderate their communities (GitHub Advisory).

The vulnerability has been patched in Mastodon versions 4.4.6, 4.3.14, and 4.2.27. No known workarounds exist for unpatched versions. Administrators should upgrade to the patched versions to ensure proper disconnection of suspended or disabled accounts from the streaming API (GitHub Advisory).