CVE-2026-26747
Critical
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,
SeverityCritical
CVSS9.1
Exploit probability—
ProductMonica
PublishedFeb 20, 2026
First seenFeb 20, 2026
Weakness typeCWE-644CWE-644
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| monicahq monica | 4.1.2 | — |
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