CVE-2026-41259 — Mastodon: Insufficient verification of email addresses
Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail d…
Published: 2026-04-23 · CVSS: 8.2 · CVSS 4.0
Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail domain names, and performs basic validation on e-mail addresses, but fails to restrict characters that are interpreted differently by some mailing servers. This vulnerability is fixed in v4.5.9, v4.4.16, and v4.3.22.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7