Security Advisory: CSF Firewall Port Rule Race Condition

This is a security release for AlmaLinux 8, AlmaLinux 9. Update the product on every affected server to the patched release — there is no workaround, and unpatched servers remain exposed until updated.

Low 2026-06-25

CSF AlmaLinux 8 AlmaLinux 9 CentOS 7 CloudLinux 7 CloudLinux 8 CloudLinux 9

Affected Versions

CSF 14.20 and earlier

Patched Version

CSF 14.21

Default Update CMD

yum update -y

Fix Commands

AlmaLinux 9 / CloudLinux 9

cd /etc/csf
csf -u
csf -r

AlmaLinux 8 / CloudLinux 8

cd /etc/csf
csf -u
csf -r

CentOS 7 / CloudLinux 7

cd /etc/csf
csf -u
csf -r

What this means under a SharedLicense license

Your SharedLicense license itself is not affected — this is a change in AlmaLinux 8, AlmaLinux 9 software, not in licensing. Update the product through its standard update channel. Licenses keep working through updates; nothing needs re-issuing or re-activating.

References

Vendor Advisory

Security Advisories

Related Advisories

ConfigServer Security & Firewall (CSF) 16.32-1 — cPanel & WHM Update

2026-09-30

EasyApache 4 25.81 — cPanel & WHM Update

2026-09-30

cPanel CVE-2026-87899: Privilege Escalation

2026-09-23 00:00:00

Check your system for vulnerabilities

Select your product and operating system to see the exact fix commands that apply to you.

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