ZeroHour

CVE-2026-54420

KEVlarge

Symlink-Following Privilege Escalation in LiteSpeed cPanel Plugin Exploited in the Wild

CISA: LiteSpeed cPanel Plugin UNIX Symbolic Link (Symlink) Following Vulnerability

CVSS 3.1
8.5 high
EPSS
1%p72
Published
()
KEV added
AI analysis

The LiteSpeed cPanel plugin, as distributed through the LiteSpeed WHM plugin, before version 2.4.8 (WHM plugin 5.3.2.0) mishandles UNIX symbolic links supplied by users (CWE-61). An attacker who already has FTP or web shell access to any account on a shared hosting server running CloudLinux/CageFS can plant a crafted symlink that the privileged plugin follows, letting them act beyond their own account scope — reportedly gaining root control of the entire server (CVSS scope change, C:H/I:H/A:H). Any hosting provider running vulnerable versions of the LiteSpeed cPanel/WHM plugin is affected, and because this is shared hosting, a single malicious tenant endangers other customers on the same server. The flaw was exploited in the wild in May 2026, was added to CISA's Known Exploited Vulnerabilities catalog on 2026-06-15 (BOD 26-04 remediation obligations apply), and has a 1.4% 30-day EPSS; no public proof-of-concept is known.

What to do: Upgrade the LiteSpeed cPanel plugin to 2.4.8 or later via the LiteSpeed WHM plugin 5.3.2.0 or later, following vendor instructions to meet CISA KEV/BOD 26-04 timelines. Until patched, restrict or monitor FTP and web shell access on affected shared hosting servers and review logs for signs of privilege escalation during and since May 2026; if mitigations are unavailable, follow applicable BOD 26-04 guidance for cloud services or discontinue use.

Affected
LiteSpeed Technologies LiteSpeed cPanel pluginbefore 2.4.8
LiteSpeed Technologies LiteSpeed WHM pluginbefore 5.3.2.0 (ships the vulnerable cPanel plugin before 2.4.8)
Estimated exposure
largeest. tens of thousands of shared hosting servers (~10^4–10^5), each hosting many customer accounts — Estimated from deployment patterns: the LiteSpeed WHM plugin is the standard distribution channel for LiteSpeed Web Server on cPanel-based shared hosting platforms, a widely used commercial web-server choice; no exact active-install count…

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description

LiteSpeed cPanel plugin before 2.4.8 (as distributed in LiteSpeed WHM PlugIn before 5.3.2.0) mishandles symlinks provided by a user with FTP or web shell access on a shared hosting server running CloudLinux/CageFS, as exploited in the wild in May 2026.

CISA Known Exploited Vulnerability
Affected
LiteSpeed cPanel Plugin
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Due date
Ransomware use
Unknown
Vendors
litespeedtech
Products
litespeed cpanel plugin, litespeed whm plugin
Weakness
CWE-61
Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

In the news

Critical cPanel Flaw Could Let One Hosting Customer Take Root Control of a Whole Server

cPanel patched critical flaw CVE-2026-65643 letting authenticated hosting customers with addon or parked domain rights execute code as root and fully compromise servers.

cPanel issued patches on August 27, 2026 for CVE-2026-65643, a flaw in domain parking and addon domain functionality in cPanel & WHM that lets an authenticated account holder create arbitrary files and execute code as root, yielding full server control. Fixed builds cover the 11.110, 11.134, 11.136 and 11.138 branches, including WP Squared 11.138.1.7, and auto-update servers receive the fix automatically. No CVSS score, published CVE record, or evidence of exploitation has appeared, and the flaw is absent from CISA's KEV catalog as of August 27. The article also recaps related 2026 cPanel-ecosystem issues, including KEV-listed LiteSpeed plugin flaws and the in-the-wild-exploited Phusion Passenger problem.

LiteSpeed Enterprise Flaw Could Let One Hosting Account Gain Root Access on a Shared Server

cPanel warns critical LiteSpeed Web Server Enterprise flaw (pre-6.3.7) lets shared-hosting account users gain root access.

A cPanel advisory published September 14 warns that a critical vulnerability in LiteSpeed Web Server Enterprise versions before 6.3.7 lets a low-privilege website user gain root access on shared-hosting servers, bypassing CageFS account isolation. LiteSpeed released version 6.3.7 on September 11, but auto-update may be delayed so admins should force the update manually. No CVE identifier, severity score, workaround, or exploitation information has been published. This is the third LiteSpeed root flaw since May, following CVE-2026-48172 and CVE-2026-54420 in the cPanel plugin, which were both actively exploited and added to CISA's KEV catalog.

Shared Hosting at Risk: LiteSpeed Enterprise Bug Can Grant Root from a Single Tenant

Critical LiteSpeed Web Server Enterprise flaw (pre-6.3.7) lets a low-privilege shared-hosting tenant escape CageFS isolation and gain root; forced update urged.

cPanel warned that a critical privilege-escalation vulnerability in LiteSpeed Web Server Enterprise (fixed in 6.3.7) lets a malicious low-privilege website user bypass account isolation controls including CloudLinux CageFS and gain root on shared-hosting servers, enabling cross-tenant compromise. No CVE, severity rating, or technical details have been published, and it is unclear whether the flaw is being exploited. This is the third root-level LiteSpeed escape on cPanel servers since May, following CVE-2026-48172 and CVE-2026-54420, which were actively exploited and added to CISA's KEV catalog.