CVE-2025-37987

What it actually does

The pds_core adminq lock serializes command posting but not completions, allowing sequential accumulation beyond the 16-entry firmware queue depth and causing permanent stuck state with no further processing or completions.

Why it matters to the business

Affected Linux kernel deployments on listed Ubuntu releases may experience unresponsive adminq-dependent hardware or drivers, leading to degraded availability and operational disruption until systems are updated.

How an attack unfolds

An attacker with local access triggers repeated sequential adminq commands from client drivers to exceed the firmware queue limit of 16, exploiting the missing overflow protection and race between posting and completion contexts to induce a stuck condition.

How to fix it

Upgrade affected packages to the listed fixed versions: linux 3.11.0-12.19, linux-aws 4.4.0-1002.2, linux-lts-xenial 4.4.0-13.29~14.04.1, linux 4.4.0-2.16, linux-aws 4.4.0-1001.10, linux-kvm 4.4.0-1004.9, linux-aws-5.15 5.15.0-1073.79~20.04.1 and later equivalents for each distribution.

How to confirm the fix worked

Verify installed kernel package versions match or exceed the fixed releases above and confirm the adminq depth limit of 16 is enforced in the running driver.

Typical attack path

1. Obtain local execution on a system running a vulnerable pds_core driver
2. Identify paths that issue adminq commands from client drivers
3. Rapidly post more than 16 sequential commands while completions are pending
4. Observe firmware queue overflow resulting in permanent stuck adminq state

How to detect it

Review kernel logs and driver traces for repeated adminq command submissions without corresponding completions or indications of queue depth warnings around the 16-command threshold.

What your security team should do

• Apply the exact fixed package versions immediately on all affected Ubuntu systems
• Prioritize systems with pds_core hardware usage due to potential availability impact
• Monitor kernel logs for adminq-related warnings after patching