CVE-2026-75872 PUBLISHED

HTML Injection in MailerUp double opt-in verification email

Assigner: Secur0
Reserved: 18.08.2026 Published: 18.08.2026 Updated: 18.08.2026

HTML Injection in the public subscription form in maalfer MailerUp before 1.1.3 allows unauthenticated remote attackers to have the application send a message carrying arbitrary HTML, to an attacker-chosen address and from the form owner's configured sending identity, via the first_name field of the subscription request, which is interpolated unescaped into the double opt-in verification email.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 6.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	maalfer
Product	MailerUp
Versions	Default: unaffected affected from 0 to 1.1.3 (excl.)

Solutions

Upgrade to version 1.1.3 or higher.

Credits

Nacho García Egea finder
Xoán M. Otero Jorge analyst
Secur0 CNA coordinator
Mario Álvarez Fernández remediation developer

References

Problem Types

CWE-80 Improper neutralization of Script-Related HTML tags in a web page (basic XSS) CWE

Impacts

CAPEC-242 Code Injection