Subject: Important: Temporary WHM/cPanel Access Limits Due to Critical Security Update

Dear Customer,

We want to make you aware of a recently disclosed critical security vulnerability in cPanel & WHM that affects almost all versions except the very latest releases. This flaw (CVE-2026-41940) is an authentication bypass bug that could allow attackers to access WHM/cPanel without a valid login, which is why hosting providers worldwide are taking emergency precautions.

To protect your data and servers, we are:

• Applying cPanel’s emergency security update as quickly as possible, using the vendor’s recommended forced update process.cpanel+2

• For servers running newer, supported versions of Linux and cPanel, we are already rolling out the patched versions.

• For some VPS, Cloud, and Dedicated servers on older/outdated Linux or unsupported cPanel versions, we may also need to migrate you to a supported environment so that you continue to receive security updates.cybersecuritynews+2

Because of the severity of this issue, we have temporarily restricted access to WHM/cPanel on certain servers while updates and migrations are in progress. This is similar to what other major hosting providers have done (for example, blocking ports 2083 and 2087 used for WHM and cPanel) to prevent attackers from exploiting this vulnerability.thehackernews+2

What this means for you:

• This only affects some VPS/Cloud/Dedicated clients, primarily those on older Linux/cPanel versions.

• Your websites and email should generally remain online, but you may not be able to log into WHM or cPanel for short periods while we patch or migrate your server.

• Once your system is updated or migrated to a secure, supported version, normal WHM/cPanel access will be restored.

If you urgently need changes (for example, adding email filters to block the current spam/scam campaigns, DNS changes, account or database changes, etc.) while your WHM/cPanel access is limited, please open a support ticket or reply to this email and our team will perform the changes for you.

We understand that access to WHM/cPanel is critical for managing your services, but protecting the security of your server and data is our top priority. We appreciate your patience while we complete these emergency updates.

Sincerely,
IONBLADE Support
+1 626.377.9979
[email protected]
www.ionblade.com

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Update:: 

https://github.com/watchtowrlabs/watchTowr-vs-cPanel-WHM-AuthBypass-to-RCE.py?ref=labs.watchtowr.com

https://labs.watchtowr.com/the-internet-is-falling-down-falling-down-falling-down-cpanel-whm-authentication-bypass-cve-2026-41940/