Monica 4.1.2 AppServiceProvider.php Host password recovery

Summaryinfo

A vulnerability marked as critical has been reported in Monica 4.1.2. Affected by this issue is some unknown functionality of the file app/Providers/AppServiceProvider.php. The manipulation of the argument Host leads to password recovery. This vulnerability is listed as CVE-2026-26747. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Monica 4.1.2. It has been rated as critical. This issue affects an unknown code of the file app/Providers/AppServiceProvider.php. The manipulation of the argument Host with an unknown input leads to a password recovery vulnerability. Using CWE to declare the problem leads to CWE-640. The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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,

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-26747 since 02/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/27/2026). The attack technique deployed by this issue is T1552 according to MITRE ATT&CK.

By approaching the search of inurl:app/Providers/AppServiceProvider.php it is possible to find vulnerable targets with Google Hacking.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

• Monica

Version

• 4.1.2

CPE 2.3info

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CPE 2.2info

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