PT-2026-21270 · Monica · Monica

Hungnqdz · Published 2026-02-20 · Updated 2026-02-23 · CVE-2026-26747

Positive Technologies (AI Summary)

CVSS v3.1

9.1

Critical

Base vector

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

Name of the Vulnerable Software and Affected Versions Monica version 4.1.2

Description A Host Header Poisoning issue exists due to improper handling of the HTTP Host header in the file app/Providers/AppServiceProvider.php. This is combined with a default misconfiguration where app.force url is not set, defaulting to "false". The application constructs absolute URLs, including those in password reset emails, using the user-supplied Host header. This allows attackers to manipulate the password reset link sent to a victim.

Recommendations Update to a newer version that contains a fix for this vulnerability.

Exploit

Fix

Weakness Enumeration

CWE-644

Related Identifiers

CVE-2026-26747

Affected Products

Monica

References · 7

• 🔥 https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md · Exploit
• https://osv.dev/vulnerability/CVE-2026-26747 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-26747 · Security Note
• https://github.com/monicahq/monica · Note
• https://twitter.com/CVEnew/status/2025809092690981075 · Twitter Post
• https://t.me/CVEtracker/45289 · Telegram Post
• https://twitter.com/TheHackerWire/status/2026054175055081548 · Twitter Post