CVE-2026-26747

Name: CVE-2026-26747
Creator: NVD / NIST
Published: 2026-02-20T17:25:56.023+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.39%

Last modified Jun 17, 2026

CVE-2026-26747 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.39% chance of exploitation in the next 30 days.

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,

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.39%

30.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-644

Affected Software

Vendor	Product	Versions
Monicahq	Monica	4.1.2

References

https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.mdExploit, Vendor Advisory
https://github.com/monicahq/monicaProduct

Timeline

Published: Feb 20, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-26747?

How severe is CVE-2026-26747?

CVE-2026-26747 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.39% probability of exploitation in the next 30 days.

How do I fix CVE-2026-26747?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-26747?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST