We would like to inform all HostRainbow clients about a recently disclosed security vulnerability affecting cPanel & WHM.

Official advisory:
https://support.cpanel.net/hc/en-us/articles/40311543760407-Security-CVE-2026-29203-cPanel-WHM-WP2-Security-Update-May-08-2026

Vulnerability ID: CVE-2026-29203
Severity: High
Affected Software: cPanel & WHM / WP Toolkit (WP2)

What is the issue?

A security vulnerability has been identified in cPanel & WHM related to WP Toolkit (WP2). Under certain conditions, the issue could allow unauthorized or unintended actions within affected environments if systems remain unpatched.

cPanel has released security updates to address this vulnerability and strongly recommends immediate updates.

What is the risk?

• Potential unauthorized actions within WP Toolkit environments

• Increased security exposure on outdated systems

• Possible exploitation if servers are left unpatched

Actions taken by HostRainbow

• All managed servers have been reviewed

• Security updates have been applied where required

• Additional monitoring and security checks have been enabled

All HostRainbow managed infrastructure is secured against this vulnerability.

Required actions for unmanaged or self-managed servers

If you manage your own VPS or dedicated server, please update cPanel & WHM immediately.

Run:

/scripts/upcp --force

Restart cPanel services:

/scripts/restartsrv_cpsrvd

Clear existing cPanel sessions (recommended):

rm -rf /var/cpanel/sessions/*

Verify cPanel version:

/usr/local/cpanel/cpanel -V

Ensure your server is running the latest patched release tier.

Recommended security checks

Review the following logs for suspicious activity:

/usr/local/cpanel/logs/access_log
/usr/local/cpanel/logs/error_log
/var/log/secure

Look for:

• Unknown login attempts

• Suspicious API activity

• Unexpected WP Toolkit actions

Additional recommendations

• Keep automatic updates enabled

• Use strong passwords and 2FA wherever possible

• Ensure firewall protection is active (CSF, Imunify360, etc.)

• Regularly review user accounts and permissions

Important note

Due to the active nature of modern hosting attacks, we strongly recommend applying updates immediately. Delayed patching may expose servers to unnecessary security risks.

Need assistance?

If you need help updating or securing your server, our support team is available to assist.

Team HostRainbow