CVE-2026-41940: cPanel & WHM login-flow authentication bypass

Exploited in the wild Critical 9.3 EPSS 98.5% cPanel & WHM

A flaw in the cPanel & WHM login flow lets an unauthenticated remote attacker gain access to the control panel without valid credentials. All cPanel & WHM versions after 11.40 and WP Squared before 11.136.1.7 are affected. Patched builds were released on 28 April 2026; CISA added it to KEV on 30 April 2026 and lists it as used in ransomware campaigns.

CVE-2026-41940CVE identifier
9.3CVSS 4.0 base score (critical)
2026-04-30added to CISA's exploited list (US federal deadline 2026-05-03)
98.5%EPSS: chance of exploitation in the next 30 days (higher than 100% of CVEs)
2026-04-29published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run cPanel & WHM and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
upcp restarts the cPanel services itself; no reboot is needed.
Because this flaw is being exploited, also check the server for signs of compromise.

Affected and fixed versions

Affected:

cPanel & WHM 11.40.0.0 before 11.86.0.41
cPanel & WHM 11.88.0.0 before 11.94.0.28
cPanel & WHM 11.96.0.0 before 11.102.0.39
cPanel & WHM 11.104.0.0 before 11.110.0.97
cPanel & WHM 11.112.0.0 before 11.118.0.63
cPanel & WHM 11.120.0.0 before 11.124.0.35
cPanel & WHM 11.126.0.0 before 11.126.0.54
cPanel & WHM 11.128.0.0 before 11.130.0.19
cPanel & WHM 11.132.0.0 before 11.132.0.29
cPanel & WHM 11.134.0.0 before 11.134.0.20
cPanel & WHM 11.136.0.0 before 11.136.0.5
WP Squared before 11.136.1.7

Fixed in:

11.86.0.41
11.94.0.28
11.102.0.39
11.110.0.97
11.118.0.63
11.124.0.35
11.126.0.54
11.130.0.19
11.132.0.29
11.134.0.20
11.136.0.5
WP Squared 11.136.1.7

Am I affected?

/usr/local/cpanel/cpanel -V

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Debian

not in distro repos: /scripts/upcp

Ubuntu

# as root
/usr/local/cpanel/scripts/upcp --force

RHEL, AlmaLinux, Rocky, Oracle

# as root; --force overrides the server's update preferences and installs the latest build for its tier
/usr/local/cpanel/scripts/upcp --force

Fedora

not supported

SUSE / openSUSE

not supported

Amazon Linux

not supported

Arch Linux

not supported

Alpine

not supported

FreeBSD

not supported

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

CISA required action: 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"

Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC and reviewed by an editor. Always confirm with your vendor's advisory.