CVE-2026-23962

The record

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 resource consumption. Depending on the number of poll options, an attacker can cause disproportionate resource usage in both Mastodon servers and clients, potentially causing Denial of Service either server-side or client-side. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

Affected packages

Related vulnerabilities

• CVE-2026-25540 Mastodon is a free, open-source social network server based on ActivityPub. Also affects mastodon
• CVE-2026-23964 Mastodon is a free, open-source social network server based on ActivityPub. Also affects mastodon
• CVE-2026-23963 Mastodon is a free, open-source social network server based on ActivityPub. Also affects mastodon
• CVE-2026-23961 Mastodon is a free, open-source social network server based on ActivityPub. Also affects mastodon
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