CVE-2026-23138 tracing: Add recursion protection in kernel stack trace recording

Medium 5.5 Published 14 Feb 2026 Updated 11 May 2026

Infinite recursion in Linux kernel stack trace recording can cause system crashes when tracing RCU events with stack trace triggers enabled.

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-2026-23138?

CVE-2026-23138 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Feb 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:

tracing: Add recursion protection in kernel stack trace recording

A bug was reported about an infinite recursion caused by tracing the rcu events with the kernel stack trace trigger enabled. The stack trace code called back into RCU which then called the stack trace again.

Expand the ftrace recursion protection to add a set of bits to protect events from recursion. Each bit represents the context that the event is in (normal, softirq, interrupt and NMI).

Have the stack trace code use the interrupt context to protect against recursion.

Note, the bug showed an issue in both the RCU code as well as the tracing stacktrace code. This only handles the tracing stack trace side of the bug. The RCU fix will be handled separately.

Which versions are affected by CVE-2026-23138?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23138?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-23138 being exploited?

There is no known exploitation of CVE-2026-23138 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-77703, BELL-CVE-2026-23138, DEBIAN-CVE-2026-23138, GHSA-gqpg-53jh-cpqf, ROOT-OS-DEBIAN-11-CVE-2026-23138, ROOT-OS-DEBIAN-12-CVE-2026-23138 and 4 more.