CVE-2026-26747: Monicahq Monica

Critical severity, CVSS 9.1. EPSS: 0.6% chance of exploitation in the next 30 days.

A Host Header Poisoning vulnerability exists in Monica 4.1.2 due to improper handling of the HTTP Host header in app/Providers/AppServiceProvider.php, combined with the default misconfiguration where the "app.force_url" is not set and default is "false". The application generates absolute URLs (such as those used in password reset emails) using the user-supplied Host header. This allows remote attackers to poison the password reset link sent to a victim,

Affected products

• Monicahq Monica: version 4.1.2 only

Published 2026-02-20. Last modified 2026-06-17.