Description
Unrestricted Upload of File with Dangerous Type vulnerability in WP Mailster WP Mailster wp-mailster allows Upload a Web Shell to a Web Server.This issue affects WP Mailster: from n/a through 1.9.1.0.
Published: 2026-10-21
Score: 10 Critical
EPSS: < 1% Very Low
KEV: No
Impact: Remote Code Execution
Action: Immediate Patch
AI Analysis

Impact

The vulnerability allows an attacker to upload an arbitrary file of a dangerous type through the plugin’s upload interface, enabling the upload of a web shell. This is a CWE-434 (Unrestricted Upload of File with Dangerous Type) vulnerability that gives a direct path to execute malicious code on the web server, jeopardizing the integrity and confidentiality of all WordPress sites that use the plugin.

Affected Systems

WordPress sites running the WP Mailster plugin up to and including version 1.9.1.0 are affected; any installation that has not yet been updated to a newer release is at risk.

Risk and Exploitability

The CVSS score of 10 reflects the high impact of arbitrary code execution, and although no EPSS value is available the lack of a KEV listing indicates no currently documented widespread exploitation. Based on the description, the attack vector is via the web interface’s upload function and could potentially be used without authentication, giving an attacker direct remote code execution capabilities.

Generated by OpenCVE AI on October 22, 2026 at 02:03 UTC.

Remediation

Vendor Solution

Update the WordPress WP Mailster plugin to the latest available version (at least 1.9.2.0).

OpenCVE Recommended Actions

  • Update the WP Mailster plugin to version 1.9.2.0 or later.
  • Immediately disable the plugin’s upload feature or restrict allowed file types to safe extensions until the update is applied.
  • Perform a security scan to locate and remove any previously uploaded malicious files and ensure proper file permissions on the server.

Generated by OpenCVE AI on October 22, 2026 at 02:03 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 10 Nov 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Thu, 22 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
First Time appeared Wordpress-extensions
Wordpress-extensions wp Mailster
Wpmailster
Wpmailster wp Mailster
Vendors & Products Wordpress-extensions
Wordpress-extensions wp Mailster
Wpmailster
Wpmailster wp Mailster

Wed, 21 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
Description Unrestricted Upload of File with Dangerous Type vulnerability in WP Mailster WP Mailster wp-mailster allows Upload a Web Shell to a Web Server.This issue affects WP Mailster: from n/a through 1.9.1.0.
Title WordPress WP Mailster plugin <= 1.9.1.0 - Arbitrary File Upload vulnerability
Weaknesses CWE-434
References
Metrics cvssV3_1

{'score': 10, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Subscriptions

Wordpress-extensions Wp Mailster
Wpmailster Wp Mailster
cve-icon MITRE

Status: PUBLISHED

Assigner: Patchstack

Published:

Updated: 2026-10-21T17:19:12.429Z

Reserved: 2026-10-17T00:17:57.460Z

Link: CVE-2026-111832

cve-icon Vulnrichment

Updated: 2026-10-21T17:09:33.825Z

cve-icon NVD

Status : Deferred

Published: 2026-10-21T15:17:15.130

Modified: 2026-10-21T18:19:16.950

Link: CVE-2026-111832

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-22T12:00:07Z

Weaknesses
  • CWE-434

    Unrestricted Upload of File with Dangerous Type