TI-2026-21384 Aliases CVE-2026-26747 GHSA-xf4f-qj26-72pf

A Host Header Poisoning vulnerability exists in Monica 4.1.2 due to improper handling of…

HIGH 78CWE-644Published 2026-02-20 · Updated 2026-02-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: High · High · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.

Summary

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,

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00444 38th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:monicahq:monica:4.1.2:::::::*	4.1.2	Vulnerable	Monicahq

cpe:2.3:a:monicahq:monica:4.1.2:*:*:*:*:*:*:* Versions 4.1.2 Vulnerable ·Monicahq

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-26747
2026-10-03 Alias added: GHSA-xf4f-qj26-72pf
2026-10-24 EPSS moved to the 50th–90th percentile
2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md

Other 1

https://github.com/monicahq/monica

TI-2024-36734 MonicaHQ v4.1.2 was discovered to contain multiple authenticated Client-Side Injection… CVSS 3.1HIGH 8.8
TI-2023-00976 Cross-site scripting in MonicaHQ CVSS 3.1HIGH 8.8
TI-2024-36737 MonicaHQ v4.1.2 was discovered to contain a Client-Side Injection vulnerability via the… CVSS 3.1MEDIUM 6.5
TI-2024-36733 MonicaHQ v4.1.2 was discovered to contain multiple Client-Side Injection vulnerabilities… CVSS 3.1MEDIUM 6.5
TI-2024-36736 MonicaHQ v4.1.2 was discovered to contain an authenticated Client-Side Injection… CVSS 3.1MEDIUM 5.4
TI-2024-36735 MonicaHQ v4.1.1 was discovered to contain an authenticated Client-Side Injection… CVSS 3.1MEDIUM 5.4

See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences