CISA Flags LiteSpeed cPanel Plugin Flaw Exploited for Root Privilege Escalation

CISA Flags LiteSpeed cPanel Plugin Flaw Exploited for Root Privilege Escalation Ravie LakshmananJun 16, 2026Vulnerability / Server Security The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added a security flaw impacting LiteSpeed cPanel Plugin to its Known Exploited Vulnerabilities (KEV) catalog, requiring Federal Civilian Executive Branch (FCEB) agencies to apply the fixes by June 18, 2026. The vulnerability in question is CVE-2026-54420 (CVSS score: 8.5), which has been described as a case of privilege escalation. It allows a user with FTP or web shell access to escalate privileges to root on shared hosting servers running CloudLinux or CageFS. "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," according to a description of the vulnerability in CVE.org. It's currently not known how the vulnerability is being exploited in the wild and if any of those attacks have been successful, but LiteSpeed has urged users to run the command below to check if their servers are affected - grep -rE 'cpanel_jsonapi_func=(generateEcCert|packageUserSize)|cert_action_entry .*geneccert' /usr/local/cpanel/logs/ /var/cpanel/logs/ 2>/dev/null If the grep command does not show any output, it indicates the server has not been impacted by the issue. If there is any output, LiteSpeed has shared additional indicators to rule out any false positives - generateEcCert immediately followed by packageUserSize for the same user (legitimate UI flows don't chain these) 7-10 concurrent calls per attempt (legitimate UI does one at a time) Namecheap has been credited with bringing the issue to its attention on May 31, 2026. Users are advised to upgrade to LiteSpeed WHM Plugin v5.3.2.1 (bundled w/ cPanel plugin v2.4.8) or higher to patch the vulnerability. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share SHARE  CISA, CloudLinux, cPanel, cybersecurity, LiteSpeed, Patch Management, privilege escalation, Shared Hosting, Vulnerability ⚡ Top Stories This Week Researchers Build Self-Replicating AI Worm That Operates Entirely on Local, Open-Weight Models Anthropic Releases Claude Fable 5, Its Most Powerful AI Yet, With Cyber Safeguards China-Linked Hackers Backdoored Linux Login Software to Hide for Nearly a Decade Agentjacking Attack Tricks AI Coding Agents Into Running Malicious Code U.S. Orders Anthropic to Suspend Fable 5 and Mythos 5 Access for Foreign Nationals Critical Splunk Enterprise Flaw Lets Attackers Run Code Without Authentication Over 400 Arch Linux AUR Packages Hijacked to Deploy Infostealer and eBPF Rootkit Microsoft Patches Record 206 Flaws, Including Three Zero-Days and Critical RCE Bugs ThreatsDay Bulletin: Worm Code Leaked, AI Agent Phished, Claude Code Patch + 28 New Stories New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files Cybersecurity Stars Awards 2026: Winners Announced Across 95 Categories Ivanti, Fortinet, and SAP Release Patches for Multiple Critical Vulnerabilities Chrome V8 Zero-Day CVE-2026-11645 Exploited in the Wild - Patch Now Microsoft Defender RoguePlanet Zero-Day Grants SYSTEM Access on Updated Windows Load More ▼ ⭐ Featured Resources Have You Outgrown Your MDR? 7 Warning Signs Every CISO Should Check Get the 2026 Guide to Govern and Secure Enterprise AI Agents at Scale AI Can’t Stop Every Attack. Learn How Zero Trust Can Block What’s Unknown [Watch Demo] See Which Security Gaps Attackers Could Exploit First