CVE-2026-30993: Slah CMS v1.5.0 RCE Vulnerability

CVE-2026-30993 Overview

A critical remote code execution (RCE) vulnerability has been identified in Slah CMS affecting version 1.5.0 and earlier releases. The vulnerability exists within the session() function located in the config.php file, which can be exploited through specially crafted input to execute arbitrary code on the target system. This vulnerability falls under CWE-94 (Improper Control of Generation of Code), commonly known as code injection.

Critical Impact

Successful exploitation allows unauthenticated remote attackers to execute arbitrary code on affected Slah CMS installations, potentially leading to complete system compromise, data theft, and further lateral movement within the network.

Affected Products

• Slah CMS version 1.5.0
• Slah CMS versions prior to 1.5.0
• All Slah CMS installations using the vulnerable config.php configuration

Discovery Timeline

• 2026-04-15 - CVE-2026-30993 published to NVD
• 2026-04-16 - Last updated in NVD database

Technical Details for CVE-2026-30993

Vulnerability Analysis

This vulnerability represents a code injection flaw in the Slah CMS content management system. The session() function within config.php fails to properly validate and sanitize user-supplied input before processing it. This lack of input validation allows attackers to inject and execute arbitrary code within the context of the web application.

Code injection vulnerabilities like this one are particularly dangerous because they enable attackers to bypass authentication mechanisms entirely and gain direct code execution on the underlying server. The network-based attack vector means this vulnerability can be exploited remotely without requiring any prior authentication or user interaction, significantly increasing the risk exposure for affected organizations.

Root Cause

The root cause of CVE-2026-30993 lies in improper input validation within the session() function in config.php. The function appears to process user-controlled data in an unsafe manner, likely through the use of dangerous PHP functions such as eval(), create_function(), or similar code execution mechanisms that interpret user input as executable code. This allows malicious payloads to be injected and executed on the server.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction to exploit. An attacker can send specially crafted HTTP requests to the vulnerable Slah CMS installation, targeting the session() function through the config.php endpoint. The malicious payload is processed by the vulnerable function and executed on the server, granting the attacker code execution capabilities.

The exploitation process involves:

1. Identifying a vulnerable Slah CMS installation
2. Crafting malicious input designed to bypass any rudimentary filtering
3. Submitting the payload to trigger the vulnerable session() function
4. Achieving arbitrary code execution on the target server

For detailed technical information about this vulnerability, refer to the CVE-2026-30993 Details and Slah Informatica RCE Overview.

Detection Methods for CVE-2026-30993

Indicators of Compromise

• Unusual HTTP requests targeting config.php with suspicious parameters or encoded payloads
• Web server logs containing attempts to inject PHP code constructs such as eval(, system(, exec(, or passthru(
• Unexpected child processes spawned by the web server process (e.g., /bin/sh, cmd.exe)
• New or modified files appearing in web directories, particularly PHP webshells
• Outbound network connections from the web server to unknown external IP addresses

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block code injection patterns targeting PHP applications
• Monitor web server access logs for requests containing suspicious PHP function names or encoded malicious payloads
• Deploy endpoint detection and response (EDR) solutions like SentinelOne to detect anomalous process execution from web server contexts
• Utilize file integrity monitoring on the Slah CMS installation directory to detect unauthorized modifications

Monitoring Recommendations

• Enable detailed logging for the web server hosting Slah CMS and forward logs to a centralized SIEM
• Configure alerts for any access attempts to config.php with query parameters outside normal application behavior
• Monitor for process chains indicative of webshell activity (web server → shell interpreter → subsequent commands)
• Implement network segmentation and monitor for lateral movement attempts originating from the CMS server

How to Mitigate CVE-2026-30993

Immediate Actions Required

• Identify all Slah CMS installations running version 1.5.0 or earlier in your environment
• Restrict network access to the CMS administrative interface and config.php to trusted IP addresses only
• Implement WAF rules to block requests containing code injection payloads
• Consider taking vulnerable instances offline until a patch is applied
• Review web server logs for any signs of prior exploitation attempts

Patch Information

At the time of publication, organizations should monitor the vendor's official channels for security updates. Refer to the CVE-2026-30993 Details page for the latest patch information and remediation guidance from the vendor.

Workarounds

• Implement strict input validation and sanitization at the web application firewall level to filter malicious payloads
• Use network-level access controls to restrict access to the Slah CMS installation from untrusted networks
• Consider disabling or removing the vulnerable session() functionality if not critical to operations
• Deploy virtual patching through WAF rules while awaiting an official vendor patch
• Isolate Slah CMS servers in a segmented network zone with restricted outbound connectivity

# Example: Apache .htaccess rule to restrict access to config.php
<Files "config.php">
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
</Files>