High severity7.5NVD Advisory· Published Apr 23, 2026· Updated Apr 28, 2026

CVE-2026-41259

Description

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

Mastodon/Mastodon
cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*
Range: <4.3.22
osv-coords
pkg:bitnami/mastodon
Range: < 4.3.22

Patches

Vulnerability mechanics

References

github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhhnvdVendor Advisory

News mentions

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