CVE-2021-33630 NULL-ptr-deref in network sched

Medium 5.5 Published 18 Jan 2024 Updated 7 May 2025

A NULL pointer dereference in the Linux kernel network scheduler allows attackers to cause a denial of service.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2021-33630?

CVE-2021-33630 is a medium-severity vulnerability in openEuler kernel, published on 18 Jan 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

NULL Pointer Dereference vulnerability in openEuler kernel on Linux (network modules) allows Pointer Manipulation. This vulnerability is associated with program files net/sched/sch_cbs.C.

This issue affects openEuler kernel: from 4.19.90 before 4.19.90-2401.3.

Weakness: CWE-476

Which versions are affected by CVE-2021-33630?

It affects 1 product.

Products include Openatom Openeuler.

How do I fix CVE-2021-33630?

Apply the vendor's patch.

Is CVE-2021-33630 being exploited?

There is no known exploitation of CVE-2021-33630 in the wild and no public exploit code.

CVE-2021-33631 Kernel crash in EXT4 filesystem Medium 5.5

Sources

Also known as DEBIAN-CVE-2021-33630, GHSA-4mwf-4888-4x35, UBUNTU-CVE-2021-33630.