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CISA KEV · ACTIVELY EXPLOITED
HIGH severity

CVE-2026-54420 — Litespeed Cpanel Plugin

HIGH

CVE-2026-54420 is a high-severity (CVSS 8.5) CWE-61 vulnerability in litespeedtech litespeed cpanel plugin. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-06-15) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.

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…

Published
Updated
Affected
2 products
Patched
See advisory
Exploits
None indexed
Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-06-15. Federal agencies were required to remediate by 2026-06-18.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-54420.

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk+0.63%
Lower risk than most CVEs73th percentile — riskier than 73% of all scored CVEsHighest risk
0.31%0.85%1.39%1.94%1.3%1.4%0.8%1.4%Jul 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-54420 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 397,508 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

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.

Affected Products

2 products · 2 configurations
Application
litespeed cpanel pluginlitespeedtech
< 2.4.8
range
Application
litespeed whm pluginlitespeedtech
< 5.3.2.0
range

Detection & mitigation playbook

Vendor / appliance

  1. Detect

    Inventory every litespeedtech litespeed cpanel plugin deployment and check each version against the affected-products list above.

  2. Fix

    Apply the litespeedtech litespeed cpanel plugin security patch or hotfix for CVE-2026-54420 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

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.
O3 Security · Runtime Protection

Is CVE-2026-54420 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Protect my workloads How runtime protection works
CVE-2026-54420: Litespeed Cpanel Plugin (High 8.5, KEV)