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4.6

Flarum Forum Software: Malicious Email Links in Nicknames

GHSA-3c4m-j3g4-hh25 CVE-2026-30913 GHSA-3c4m-j3g4-hh25
Summary

When using the Nicknames extension in Flarum forum software, a registered user can create a nickname that looks like a link. This can trick email clients into turning the nickname into a clickable link in notification emails, potentially leading recipients to malicious websites. To address this, update the Flarum software and configure the Nicknames extension to prevent this behavior.

What to do
  • Update flarum nicknames to version 1.8.3.
  • Update flarum flarum/nicknames to version 1.8.3.
Affected software
VendorProductAffected versionsFix available
flarum nicknames <= 1.8.3 1.8.3
flarum flarum/nicknames <= 1.8.3 1.8.3
Original title
Flarum is open-source forum software. When the flarum/nicknames extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname ...
Original description
Flarum is open-source forum software. When the flarum/nicknames extension is enabled, a registered user can set their nickname to a string that email clients interpret as a hyperlink. The nickname is inserted verbatim into plain-text notification emails, and recipients may be misled into visiting attacker-controlled domains.
ghsa CVSS3.1 4.6
Vulnerability type
CWE-79 Cross-site Scripting (XSS)
Published: 10 Mar 2026 · Updated: 13 Mar 2026 · First seen: 10 Mar 2026