Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 97.9%; technical severity is CVSS 9.3.
cPanel and WHM versions after 11.40 contain an authentication bypass vulnerability in the login flow that allows unauthenticated remote attackers to gain unauthorized access to the control panel.
Who should care
- Teams operating Cpanel, Whm, Wp Squared +1 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Cpanel, Whm, Wp Squared +1 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Vendor remediation
Patch and remediation links
Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.
Technical details
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CWE
- CWE-306
- Affected versions
- Cpanel Cpanel (Start Including: 136.0.0, End Excluding: 136.0.5); Cpanel Whm (Start Including: 136.0.0, End Excluding: 136.0.5); Cpanel Wp Squared (End Excluding: 136.1.7); WebPros cPanel & WHM and WP2 (WordPress Squared)
- Published
- 29 April 2026
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- Added to CISA KEV
- Latest EPSS score: 97.9%
- Signal calculated at 87
External references
- Exploit information from github.com
- Government advisory from www.cisa.gov
- Exploit information from labs.watchtowr.com
- Technical reference from www.bleepingcomputer.com
- Release notes from docs.cpanel.net
- Release notes from docs.wpsquared.com
- Vendor advisory from support.cpanel.net
- Third-party advisory from www.namecheap.com
- Third-party advisory from www.vulncheck.com