CVE-2026-72916

Mastodon, a free, open-source social network server based on ActivityPub, has a vulnerability in its protection mechanism that blocks requests to local IP addresses. Some IP address ranges are missing, allowing an attacker to make Mastodon perform HTTP requests against loopback or local network hosts, potentially accessing private resources and services. This is fixed in Mastodon v4.5.4, v4.4.11, v4.3.17 and v4.2.29.

Mastodon, an ActivityPub-based social network server, has a vulnerability that allows attackers to create and overwrite arbitrary files in the system through carefully crafted media files. This affects versions from 3.5.0 to 3.5.8 and 4.0.0 to 4.1.2.

Mastodon, an ActivityPub-based social network server, has a vulnerability that allows attackers to bypass HTML sanitization using crafted oEmbed data. This enables the injection of arbitrary HTML into oEmbed preview cards, creating a vector for XSS attacks.

Vulnerability in Mastodon prior to versions 4.4.19 and 4.5.12. The ldap_authenticable.rb file mutates global OpenSSL parameters when LDAP uses LDAP_TLS_NO_VERIFY=true, disabling SSL/TLS certificate verification for puma web processes.

Mastodon is a free, open-source social network server based on ActivityPub. From 4.6.0-beta.1 until 4.6.4 and 4.7.0-beta.1, any logged-in local user could use the show action in app/controllers/admin/collections_controller.rb to access personally identifying information about another local user in a collection because the controller used the general collection policy instead of the admin collection policy namespace. The exposed data included the other user's current email address and last-used IP address. This issue is fixed in versions 4.6.4 and 4.7.0-beta.1.

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, the administrative statistics endpoints handled by Api::V1::Admin::MeasuresController and Api::V1::Admin::RetentionController checked authorization only after beginning expensive calculations. Anonymous callers could submit keys, start_at, and end_at parameters that caused long-running SQL queries in Admin::Metrics::Measure, Admin::Metrics::Retention, and Admin::Metrics::Dimension::BaseDimension, allowing repeated requests to exhaust server resources. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1.

Mastodon prior to versions 4.5.11, 4.4.18, and 4.3.24 contains a DoS vulnerability due to missing exception handling in the math sanitizer. Malformed <math> nodes can lead to a DoS of the entire server or targeted user services, depending on the actions involving those nodes.

Mastodon, a social network server based on ActivityPub, has a vulnerability in versions from 4.3.0 to 4.5.11 and 4.4.18 that allows modification of the attributionDomains value in signed activities. An error in the definition of this term makes Linked Data signatures ineffective.

Prior to versions 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures did not adequately protect against a certain class of spoofing, allowing threat actors to remove JSON entries from valid signed activities from third-party actors.

Mastodon prior to versions 4.5.10, 4.4.17, and 4.3.23 has a vulnerability that allows incorrect recognition of IPv4-mapped IPv6 addresses, potentially leading to TCP connections to private IPv4 addresses. Attackers can exploit this vulnerability by publishing appropriate DNS records.