CVE-2026-26747

moderate-risk
Published 2026-02-20

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,

Do I need to act?

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0.08% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
9
CVSS 9.1/10 Critical
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Monicahq

References (2)

Exploit https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md
Product https://github.com/monicahq/monica
36
/ 100
moderate-risk
Severity 31/34 · Critical
Exploitability 0/34 · Minimal
Exposure 5/34 · Minimal