cPanel ConfigServer Security & Firewall Vulnerability Allows Remote Attacker to Execute Arbitrary Commands
CSF 14.00–16.29 (CVE-2026-65638) lets unauthenticated attackers execute arbitrary commands via the MESSENGER service on cPanel/WHM servers; version 16.30 fixes it.
CVE-2026-65638 affects ConfigServer Security & Firewall (CSF) versions 14.00 through 16.29 and allows unauthenticated remote attackers to execute arbitrary commands through the MESSENGER service, running under the unprivileged CSF service account rather than root. Exploitation requires the non-default MESSENGER service to be enabled and a reCAPTCHA secret configured, reducing exposure for standard deployments. CSF 16.30 and later fix the flaw; administrators who cannot update immediately can set MESSENGER = 0 in /etc/csf/csf.conf as a temporary mitigation.
cPanel Urges Users to Patch ConfigServer Firewall Remote Code Execution Flaw
cPanel urges administrators to patch CVE-2026-65638, a flaw letting unauthenticated attackers run commands through ConfigServer Firewall's MESSENGER service; update to CSF 16.30.
CVE-2026-65638 in ConfigServer Security & Firewall (CSF) 14.00–16.29 allows unauthenticated remote attackers to execute arbitrary commands via the MESSENGER service, which is exposed only when MESSENGER is enabled and a reCAPTCHA secret has been configured. Exploitation yields command execution under the unprivileged CSF service account, providing a foothold for reconnaissance, data access, or lateral movement on internet-facing cPanel/WHM hosting infrastructure. CSF 16.30 or later fixes the issue; disabling MESSENGER in /etc/csf/csf.conf and restarting csf and lfd is a temporary mitigation.
2026-005: High Vulnerability in the Linux Kernel ("Copy Fail")
Linux kernel flaw CVE-2026-31431 ('Copy Fail', CVSS 7.8) allows unprivileged users to gain root via AF_ALG; a public PoC is out and most distros remain unpatched.
Disclosed on 29 April 2026, CVE-2026-31431 is a local privilege escalation in the Linux kernel's algif_aead module (AF_ALG crypto API), CVSS 7.8, stemming from a 2017 in-place optimisation. By chaining an AF_ALG socket operation with splice(), an unprivileged user can write 4 bytes into an arbitrary page-cache page, e.g. corrupting a setuid binary like /usr/bin/su to obtain a root shell. It affects virtually all kernels built since 2017, including Ubuntu 20.04-24.04, Amazon Linux 2023, RHEL 10.1, and SUSE 16; the mainline fix landed 1 April 2026 but no vendor packages were available as of 30 April. CERT-EU recommends the interim mitigation (disable algif_aead) and blocking AF_ALG via seccomp, prioritising Kubernetes nodes and CI/CD runners.