CVE-2026-23131

What it actually does

Missing input validation in hp-bioscfg allows WMI buffers containing empty attribute name strings to reach kobject registration, triggering repeated kernel warnings at lib/kobject.c and potentially destabilizing the module or system availability.

Why it matters to the business

On affected HP systems running the listed kernel, administrators may observe kernel warnings or experience availability disruptions when the BIOS exposes malformed attributes, increasing operational overhead until systems are updated.

How an attack unfolds

An attacker with local low-privileged access on a vulnerable HP platform triggers the hp-bioscfg driver during boot or module load; the driver parses an empty name from the WMI buffer and attempts kobject_add_internal, producing warnings that can be leveraged to degrade service.

How to fix it

Upgrade linux-aws-5.4 packages to version 5.4.0-1109.118~18.04.1 or later on Ubuntu Pro 18.04 LTS systems; after reboot verify the module no longer registers empty-named kobjects.

How to confirm the fix worked

Confirm installed kernel version matches or exceeds the fixed release, then load the module while monitoring dmesg for absence of the kobject empty-name warning and successful registration of valid attributes only.

Typical attack path

1. Obtain local user access on affected Ubuntu 18.04 AWS instance with HP hardware
2. Ensure hp-bioscfg module loads or trigger BIOS attribute enumeration
3. Supply or induce WMI buffer with empty attribute names
4. Observe kernel warnings and potential module or system impact

How to detect it

Search kernel logs (dmesg, /var/log/kern.log, journalctl) for the exact kobject registration warning and the WARNING line from lib/kobject.c; correlate with hp-bioscfg module load events on HP platforms.

• kobject: (00000000135fb5e6): attempted to be registered with empty name!
• WARNING: CPU:.*PID:.*at lib/kobject.c:219 kobject_add_internal+0x2eb/0x310
• hp_init_bios_buffer_attribute

What your security team should do

• Prioritize patching all linux-aws-5.4 instances to 5.4.0-1109.118~18.04.1 within standard change windows
• Add the kobject empty-name warning string to SIEM rules for proactive detection until patches are complete
• Review HP BIOS configurations on affected hardware to identify systems returning empty attribute names