# CVE-2026-46196: tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

> A kernel bug causes persistent syscall tracing overhead after a failed probe registration, leading to performance degradation until reboot.

- **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:** 28 May 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-89079, BELL-CVE-2026-46196, DEBIAN-CVE-2026-46196, GHSA-3j98-4vrc-2fpm, ROOT-OS-DEBIAN-11-CVE-2026-46196, ROOT-OS-DEBIAN-12-CVE-2026-46196, ROOT-OS-UBUNTU-2204-CVE-2026-46196, ROOT-OS-UBUNTU-2404-CVE-2026-46196, UBUNTU-CVE-2026-46196

## What is CVE-2026-46196?

CVE-2026-46196 is a medium-severity denial of service vulnerability in Linux kernel, published on 28 May 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:

tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func()
invokes the subsystem's ext->regfunc() before attempting to install the
new probe via func_add(). If func_add() then fails (for example, when
allocate_probes() cannot allocate a new probe array under memory pressure
and returns -ENOMEM), the function returns the error without calling the
matching ext->unregfunc(), leaving the side effects of regfunc() behind
with no installed probe to justify them.

For syscall tracepoints this is particularly unpleasant: syscall_regfunc()
bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.
After a leaked failure, the refcount is stuck at a non-zero value with no
consumer, and every task continues paying the syscall trace entry/exit
overhead until reboot. Other subsystems providing regfunc()/unregfunc()
pairs exhibit similarly scoped persistent state.

Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the
func_add() error path, gated on the same condition used there so the
unwind is symmetric with the registration.

## Which versions are affected by CVE-2026-46196?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46196?

Apply the vendor's patch.

## Is CVE-2026-46196 being exploited?

There is no known exploitation of CVE-2026-46196 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-2026-46196 and fix it if it is affected.

What it is: CVE-2026-46196 is a medium-severity denial of service vulnerability in Linux kernel, published on 28 May 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-2026-46196 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-2026-46196/ (Markdown: https://insights.sbomify.com/CVE-2026-46196/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46196
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46196
- OSV: https://osv.dev/vulnerability/CVE-2026-46196

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46196/
Summaries are generated and may contain mistakes; the official description above is the record.