Claire

31 exploits Active since Jul 2023
CVE-2025-54879 WRITEUP MEDIUM WRITEUP
Mastodon 3.1.5-4.2.24, 4.3.0-4.3.11, 4.4.0-4.4.3 - Denial of Service via Email Confirmation Rate Limit Bypass
Mastodon is a free, open-source social network server based on ActivityPub Mastodon which facilitates LDAP configuration for authentication. In versions 3.1.5 through 4.2.24, 4.3.0 through 4.3.11 and 4.4.0 through 4.4.3, Mastodon's rate-limiting system has a critical configuration error where the email-based throttle for confirmation emails incorrectly checks the password reset path instead of the confirmation path, effectively disabling per-email limits for confirmation requests. This allows attackers to bypass rate limits by rotating IP addresses and send unlimited confirmation emails to any email address, as only a weak IP-based throttle (25 requests per 5 minutes) remains active. The vulnerability enables denial-of-service attacks that can overwhelm mail queues and facilitate user harassment through confirmation email spam. This is fixed in versions 4.2.24, 4.3.11 and 4.4.3.
CVSS 5.3
CVE-2025-62174 WRITEUP LOW WRITEUP
Mastodon < 4.2.27 - Insufficient Session Expiration via Password Reset
Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon before 4.4.6, 4.3.14, and 4.2.27, when an administrator resets a user account's password via the command-line interface using `bin/tootctl accounts modify --reset-password`, active sessions and access tokens for that account are not revoked. This allows an attacker with access to a previously compromised session or token to continue using the account after the password has been reset. This issue has been patched in versions 4.2.27, 4.3.14, and 4.4.6. No known workarounds exist.
CVSS 3.5
CVE-2025-62175 WRITEUP MEDIUM WRITEUP
Mastodon <4.4.6, 4.3.14, 4.2.27 - Info Disclosure
Mastodon is a free, open-source social network server based on ActivityPub. In versions before 4.4.6, 4.3.14, and 4.2.27, 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 to establish new streaming connections, even though they cannot interact with other API endpoints. This undermines moderation actions, as administrators expect disabled or suspended accounts to be fully disconnected from the service. This issue has been patched in versions 4.4.6, 4.3.14, and 4.2.27. No known workarounds exist.
CVSS 4.3
CVE-2025-62605 WRITEUP MEDIUM WRITEUP
Mastodon 4.4.0-4.4.7 - Quote Control Bypass via Reblog
Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon version 4.4, support for verifiable quote posts with quote controls was added, but it is possible for an attacker to bypass these controls in Mastodon versions prior to 4.4.8 and 4.5.0-beta.2. Mastodon internally treats reblogs as statuses. Since they were not special-treated, an attacker could reblog any post, then quote their reblog, technically quoting themselves, but having the quote feature a preview of the post they did not get authorization for with all of the affordances that would be otherwise denied by the quote controls. This issue has been patched in versions 4.4.8 and 4.5.0-beta.2.
CVSS 4.3
CVE-2026-22245 WRITEUP HIGH WRITEUP
Mastodon < 4.2.29 - Server-Side Request Forgery via IP Address Range Bypass
Mastodon is a free, open-source social network server based on ActivityPub. By nature, Mastodon performs a lot of outbound requests to user-provided domains. Mastodon, however, has some protection mechanism to disallow requests to local IP addresses (unless specified in `ALLOWED_PRIVATE_ADDRESSES`) to avoid the "confused deputy" problem. The list of disallowed IP address ranges was lacking some IP address ranges that can be used to reach local IP addresses. An attacker can use an IP address in the affected ranges to make Mastodon perform HTTP requests against loopback or local network hosts, potentially allowing access to otherwise private resources and services. This is fixed in Mastodon v4.5.4, v4.4.11, v4.3.17 and v4.2.29.
CVSS 7.5
CVE-2026-22246 WRITEUP MEDIUM WRITEUP
Mastodon < 4.3.17 - Unauthenticated Information Disclosure via Severed Relationship Notifications
Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.
CVSS 6.5