CVE-2026-26747

PoC —

CVSS 3.1

9.1 critical

EPSS

<1%p33

Published

Feb 20, 2026 (Feb 20, 2026)

Modified

Jun 17, 2026

Description

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,

Vendors: monicahq
Products: monica
Weakness: CWE-644
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

NVD CVE.org GitHub PoCs EPSS (0.4%)

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