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

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

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 14 Feb 2026
- **Updated:** 11 May 2026
- **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, ROOT-OS-DEBIAN-13-CVE-2026-23138, ROOT-OS-UBUNTU-2204-CVE-2026-23138, ROOT-OS-UBUNTU-2404-CVE-2026-23138, UBUNTU-CVE-2026-23138

## 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: Linux kernel.

## How do I fix CVE-2026-23138?

Apply the vendor's patch.

## Is CVE-2026-23138 being exploited?

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

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23138 and fix it if it is affected.

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

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-23138/ (Markdown: https://insights.sbomify.com/CVE-2026-23138/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23138
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23138
- OSV: https://osv.dev/vulnerability/CVE-2026-23138

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23138/
Summaries are generated and may contain mistakes; the official description above is the record.