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Vulnerabilities

Vulnerability · CVE-2026-26747

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 th…

Published Feb 20, 2026 · catalog updated Jun 17, 2026 · the affected product

Check if you run it

No confirmed exploitation is on record for CVE-2026-26747. EPSS is 0.58%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.58%
Remediation
Not established
Affected products
cpe monicahq/monica

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,

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe monicahq/monica4.1.2

How to fix CVE-2026-26747

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-26747. EPSS is 0.58%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with 4.1.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-644: Improper Neutralization of HTTP Headers for Scripting Syntax. EPSS 0.58%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 20, 2026 · NIST NVD

    Detected

    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 att

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 att

Sources

  • CVE.orgVulnerability recordCVE-2026-26747

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-26747

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-26747

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.