CVE-2023-0590

What it actually does

A use-after-free vulnerability in qdisc_graft within net/sched/sch_api.c caused by a race condition leads to kernel memory corruption and denial of service.

Why it matters to the business

Local denial of service can cause system crashes and downtime on Linux systems handling network traffic, increasing operational disruption risk for servers and appliances.

How an attack unfolds

An attacker with local access triggers concurrent operations on network scheduler objects to hit the race in qdisc_graft, freeing memory that is later reused and resulting in a kernel crash.

How to fix it

Update the Linux kernel to include commit 830b3c68c1fb1e9176028d02ef86f3cf76aa2476 or a later equivalent fix in the affected distribution.

How to confirm the fix worked

Confirm the fix commit is present in the running kernel source tree or verify the kernel package version contains the patch.

Typical attack path

1. Gain local user access on an affected Linux system
2. Execute code that manipulates qdisc objects in parallel to trigger the race condition
3. Cause use-after-free in qdisc_graft leading to kernel panic or DoS

How to detect it

Review kernel logs for oops, panic, or warning messages referencing sch_api.c or qdisc_graft operations around the time of suspected incidents.

What your security team should do

• Apply the referenced kernel commit or distribution update immediately on exposed systems
• Limit local user privileges and network configuration access until patched
• Monitor kernel logs for related oops or panic events during the remediation window