Critical cPanel & WHM Vulnerability Exploited as Zero-Day for Months
Source SecurityWeek
Exploited in the wild · KEV due 3 May 2026 · public exploit available (Metasploit, Exploit-DB) : upgrade to 11.136.1.7 now.
Data as of 31 Oct 2026, 08:20 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- Patch
- Available – fixed in 11.136.1.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 29 Apr 2026
Detectable: evidence found.
nuclei template: cPanel & WHM - Authentication Bypass via Session-File CRLF Injection
Weaponized: evidence found.
1 Metasploit module · 1 Exploit-DB entry, 27 days after disclosure
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 1 day after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by VulnCheck
, 7 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 56 minutes after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed · ransomware use known
, 1 day after disclosure
KEV remediation due
US federal deadline
, 4 days after disclosure
First Exploit-DB entry (opens in a new tab)
cPanel - CRLF Injection
, 27 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade WP Squared to 11.136.1.7.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| WebProscPanel | Affected
| Fixed in– |
| WebProsWP Squared | Affected
| Fixed in
|
| WebProsWHM | Affected
| Fixed in– |
GitHubwebpros/cpanelpkg:github/webpros/cpanelOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Official patches addressing this vulnerability have been released in cPanel & WHM versions 11.86.0.41, 11.110.0.97, 11.118.0.63, 11.126.0.54, 11.130.0.19, 11.132.0.29, 11.136.0.5, and 11.134.0.20, as well as WP Squared version 136.1.7. It is strongly recommended to immediately update to one of these patched versions. If running unsupported versions, upgrading to a supported version eligible for the update is highly advised. Hosting providers have also mitigated risk by blocking access to cPanel & WHM ports during patch deployment. Detection scripts published by cPanel and WatchTowr should be used to identify signs of compromise. Patch status is confirmed as official fix available.
Description
A critical authentication bypass vulnerability (CVE-2026-41940) in cPanel & WHM has been exploited as a zero-day for months, allowing remote unauthenticated attackers to gain administrative access to affected servers. This flaw affects all versions after 11.40 and enables attackers to take control of the cPanel host system, modify server configurations, and potentially compromise all websites on shared hosting servers. The vulnerability involves manipulation of session files and cookies during the login flow. Multiple hosting providers have blocked access and deployed patches included in various cPanel versions starting from 11.86.0.41 onward. Detection tools have been released to identify signs of compromise. Immediate patching is strongly recommended to mitigate the risk.