Paper/Archive/CVE-2026-26747

CVE-2026-26747

mitre — A Host Header Poisoning vulnerability exists in Monica 4.1.2 due to improper handling of the HTTP Host header in app/Providers/AppService…

EPSS 0.4%public exploit CVSS 9.1

critical.is priorityof 100

CVSS 9.1 (ADP)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 38.7.387 × 207.7 Exploit: SSVC poc+1010.0 SSVC exploitation: poc+100.0

Description · from the CVE record

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,

Affected

ProductAffectedFixed inSource

n/an/a–CNA

Scores by source

CISA ADP9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: partial

References

refgithub.com/monicahq/monica refgithub.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md