SB20260409111 - Backdoor in Nextend Smart Slider 3 Pro plugin for WordPress
Published: April 9, 2026
Security Bulletin ID
SB20260409111
Severity
Critical
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Embedded malicious code (backdoor) (CVE-ID: N/A)
The vulnerability allows a remote attacker to gain unauthorized access to the application.
The vulnerability exists due to presence of embedded malicious functionality in the application code (aka backdoor) that allows a remote attacker to gain unauthorized access to the application.
Note, an unauthorized party gained access to Nextend update infrastructure on April 7 and distributed a fully attacker-authored build through the official update channel. Only version 3.5.1.35 contained the backdoor code.
Remediation
Install update from vendor's website.