CVE-2026-23963 Mastodon missing length limits on list names, filter names, and filter keywords

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or...

CVE-2026-23963

CVE-2026-23963 affects Mastodon prior to versions 4.5.5, 4.4.12, and 4.3.18 where there is no maximum length enforcement for list names, filter names, or filter keywords. This can enable a local user to craft arbitrarily long strings, leading to disproportionate storage and compute resource usage...

CVE-2026-23963 Mastodon missing length limits on list names, filter names, and filter keywords

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or...

CVE-2026-23962

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing...

EUVD-2026-4208

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing...

CVE-2026-23962 Mastodon vulnerable to Denial of Service from a single post (client/server)

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing...

CVE-2026-23962 Mastodon vulnerable to Denial of Service from a single post (client/server)

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing...

CVE-2026-23962

Mastodon is vulnerable to Denial of Service due to an unlimited maximum number of poll options for remote posts in versions before v4.3.18, v4.4.12, and v4.5.5. The underlying issue allows an attacker to create polls with a very large number of options, leading to disproportionate resource usage ...

CVE-2026-23962 Mastodon vulnerable to Denial of Service from a single post (client/server)

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing...

CVE-2026-23961 Mastodon may allow a remote suspension bypass

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under...

CVE-2026-23961

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under...

CVE-2026-23961

Summary of CVE-2026-23961 (Mastodon): A logic flaw in how suspended remote users are handled allows old posts from those users to appear in timelines, and under some circumstances, newly created posts from suspended users can be processed and surfaced. Affected releases span multiple lines: v4.5....

CVE-2026-23961 Mastodon may allow a remote suspension bypass

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under...

EUVD-2026-4207

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under...

CVE-2026-23961 Mastodon may allow a remote suspension bypass

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under...

PT-2026-3900

Name of the Vulnerable Software and Affected Versions Mastodon versions prior to 4.3.18 Mastodon versions prior to 4.4.12 Mastodon versions prior to 4.5.5 Description Mastodon is a free, open-source social network server based on ActivityPub. Versions of Mastodon prior to 4.3.18, 4.4.12, and 4.5....

Mastodon security vulnerabilities

Mastodon is an open-source social networking server based on ActivityPub. Versions of Mastodon prior to v4.5.5, v4.4.12, and v4.3.18 contained security vulnerabilities. These vulnerabilities stemmed from the lack of enforcing a maximum length for list names, filter names, or filter keywords, whic...

PT-2026-3898

Name of the Vulnerable Software and Affected Versions Mastodon versions 4.2.26 through 4.2.29 Mastodon versions 4.3.13 through 4.3.17 Mastodon versions 4.4.5 through 4.4.11 Mastodon versions 4.5.0 through 4.5.4 Description Mastodon is a social network server that allows administrators to suspend...

Mastodon security vulnerabilities

Mastodon is an open-source social networking server based on ActivityPub. Mastodon has a security vulnerability, which stems from a logical error that allows old posts of suspended users to appear on the timeline. In certain versions, this suspension mechanism may be partially bypassed...

Mastodon security vulnerabilities

Mastodon is an open-source social networking server based on ActivityPub. Versions of Mastodon prior to v4.5.5, v4.4.12, and v4.3.18 contained security vulnerabilities. These vulnerabilities stemmed from insecure direct object references in the web push subscription update endpoint, which could...