CVE-2021-47141

What it actually does

NULL pointer dereference when freeing notification blocks by indexing priv->msix_vectors after a prior allocation failure in abort_with_msix_vectors, triggered on driver unload.

Why it matters to the business

Potential kernel crashes or system instability during driver unload operations, increasing downtime risk for affected Linux systems; low urgency given absent KEV status and flat EPSS trend.

How an attack unfolds

An attacker with local access causes the gve driver to fail msix_vectors allocation then triggers unload, dereferencing the NULL pointer to crash the system.

How to fix it

Update to fixed package versions: libsepol-static (AlmaLinux:8) 2.9-3.el8, libsepol (AlmaLinux:8) 2.9-3.el8, libsepol-devel (AlmaLinux:8) 2.9-3.el8. Apply kernel patches addressing the gve NULL check.

How to confirm the fix worked

Confirm updated packages are installed via package manager queries; verify kernel source includes NULL checks before msix_vectors indexing in irq free paths.

Typical attack path

1. Trigger conditions leading to failed msix_vectors allocation in gve driver
2. Unload the driver module
3. Kernel dereferences NULL priv->msix_vectors during irq freeing

How to detect it

Search kernel logs and dmesg for NULL pointer dereference messages during gve module unload; review audit logs for driver load/unload sequences around crash times.

What your security team should do

• Prioritize patching systems using the gve driver or listed libsepol packages to the specified fixed versions
• Monitor for driver unload events in high-availability environments
• Review logs for NULL pointer dereference signatures during module removal