CVE-2026-23437 net: shaper: protect late read accesses to the hierarchy

What is CVE-2026-23437?

CVE-2026-23437 is a high-severity vulnerability in Linux kernel, published on 3 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

net: shaper: protect late read accesses to the hierarchy

We look up a netdev during prep of Netlink ops (pre- callbacks) and take a ref to it. Then later in the body of the callback we take its lock or RCU which are the actual protections.

This is not proper, a conversion from a ref to a locked netdev must include a liveness check (a check if the netdev hasn't been unregistered already). Fix the read cases (those under RCU). Writes needs a separate change to protect from creating the hierarchy after flush has already run.

Weakness: CWE-662

Which versions are affected by CVE-2026-23437?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23437?

Apply the vendor's patch.

Is CVE-2026-23437 being exploited?

There is no known exploitation of CVE-2026-23437 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-23437, DEBIAN-CVE-2026-23437, GHSA-9wj8-78x3-52f8, UBUNTU-CVE-2026-23437.