CVE-2021-47149

What it actually does

Null pointer dereference in fmvj18x_get_hwinfo when ioremap fails, resulting in memory corruption or kernel panic.

Why it matters to the business

Potential system crashes or denial of service on affected Linux systems using the Fujitsu network driver, increasing operational downtime risk on older kernels.

How an attack unfolds

An attacker with local access or ability to influence hardware initialization triggers the ioremap failure path in the Fujitsu Ethernet driver, causing the kernel to dereference a null pointer and crash the system.

How to fix it

Update affected packages to the listed fixed versions: mod_md to 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa, httpd and related modules (httpd, httpd-devel, httpd-filesystem, httpd-manual, httpd-tools, mod_ldap, mod_proxy_html, mod_session, mod_ssl) to 2.4.37-43.module_el8.5.0+2631+6f259f31.3.alma or equivalent 1:2.4.37-43 variants.

How to confirm the fix worked

Verify installed package versions match or exceed the fixed releases; inspect kernel source for the added ioremap return-value check in fmvj18x_get_hwinfo.

Typical attack path

1. Gain local access or control hardware initialization on target system
2. Force ioremap failure in fmvj18x_get_hwinfo during driver probe
3. Trigger null pointer dereference to induce kernel panic

How to detect it

Search kernel logs and dmesg output for null pointer dereference messages referencing fmvj18x_get_hwinfo or fujitsu driver initialization failures.

What your security team should do

• Apply the listed package updates immediately on AlmaLinux 8 systems
• Reboot systems after update to load corrected kernel modules
• Monitor kernel logs for related driver probe failures during routine maintenance