CVE-2026-75872
HTML Injection in MailerUp double opt-in verification email
Description
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.
INFO
Published Date :
Aug. 18, 2026, 3:17 p.m.
Last Modified :
Aug. 18, 2026, 3:17 p.m.
Remotely Exploit :
Yes !
Source :
4daa8cea-433a-44bd-9456-53b127fc289a
Affected Products
The following products are affected by CVE-2026-75872
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 4daa8cea-433a-44bd-9456-53b127fc289a | ||||
| CVSS 4.0 | MEDIUM | 4daa8cea-433a-44bd-9456-53b127fc289a |
Solution
- Update maalfer MailerUp to version 1.1.3 or later.
- Validate and sanitize all user input.
- Implement proper output encoding.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-75872.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-75872 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-75872
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-75872 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-75872 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 4daa8cea-433a-44bd-9456-53b127fc289a
Aug. 18, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/maalfer/mailerup', 'vendor': 'maalfer', 'modules': ['Public subscription form'], 'product': 'MailerUp', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '1.1.3', 'versionType': 'semver'}], 'programFiles': ['backend/apps/forms/views.py'], 'defaultStatus': 'unaffected'}] Added Description 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-80 Added Reference https://github.com/maalfer/mailerup/commit/da4aedc9621911df4ce0cc8f0b321dd6d10f40a5 Added Reference https://github.com/maalfer/mailerup/releases/tag/v1.1.3 Added Reference https://secur0.com/en/cna/cve-list/cve-2026-75872-html-injection-in-mailerup-double-optin-verification-email