CVE-2026-41940
WebPros cPanel & WHM and WP2 (WordPress Squared) Missing Authentication for Critical Function Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 May 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 4.0
- 9.3 CRITICALCVSS: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/M
- EPSS
- 98.53% probability · 100th percentile
- CISA KEV
- Listed 30 April 2026 · due 3 May 2026 · used in ransomware campaigns
- Weakness
- CWE-306
- Affected
- cpanel/cpanel · cpanel/whm · cpanel/wp squared
- Source
- disclosure@vulncheck.com
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://support.cpanel.net/hc/en-us/articles/40073787579671-cPanel-WHM-Security-Update-04-28-2026 ; https://docs.cpanel.net/release-notes/release-notes/ ; https://docs.wpsquared.com/changelogs/versions/changelog/#13617 ; https://nvd.nist.gov/vuln/detail/CVE-2026-41940"
References
- https://docs.cpanel.net/release-notes/release-notesRelease Notes
- https://docs.wpsquared.com/changelogs/versions/changelog/#13617Release Notes
- https://support.cpanel.net/hc/en-us/articles/40073787579671-cPanel-WHM-Security-Update-04-28-2026Vendor Advisory
- https://www.namecheap.com/status-updates/ongoing-critical-security-vulnerability-in-cpanel-april-28-2026Third Party Advisory
- https://www.vulncheck.com/advisories/cpanel-and-whm-authentication-bypass-via-login-flowThird Party Advisory
- https://labs.watchtowr.com/the-internet-is-falling-down-falling-down-falling-down-cpanel-whm-authentication-bypass-cve-2026-41940/Exploit, Third Party Advisory
- https://www.bleepingcomputer.com/news/security/critrical-cpanel-flaw-mass-exploited-in-sorry-ransomware-attacks/Press/Media Coverage
- https://github.com/watchtowrlabs/watchTowr-vs-cPanel-WHM-AuthBypass-to-RCE.pyExploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41940US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.