# CVE-2026-90273: coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf enable

> A missing function call in the Linux kernel's CoreSight ETM4x driver causes a reference count leak, potentially leading to resource exhaustion and denial of service.

- **Severity:** Not scored
- **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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-102999, BELL-CVE-2026-90273, DEBIAN-CVE-2026-90273, GHSA-24qc-78x7-rfr3, UBUNTU-CVE-2026-90273

## What is CVE-2026-90273?

CVE-2026-90273 is a denial of service vulnerability in Linux, published on 17 Sep 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:

coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf enable

In the perf enable path, there are missing cases where
cscfg_csdev_disable_active_config() is not called:

  - Branch broadcast is selected but not supported by the hardware
  - etm4_enable_hw() fails

This can lead to a leak of config_desc->active_cnt.
Fix this by properly calling cscfg_csdev_disable_active_config()
in these error paths.

## Which versions are affected by CVE-2026-90273?


## How do I fix CVE-2026-90273?

Apply the vendor's patch.

## Is CVE-2026-90273 being exploited?

There is no known exploitation of CVE-2026-90273 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90273 and fix it if it is affected.

What it is: CVE-2026-90273 is a denial of service vulnerability in Linux, published on 17 Sep 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-2026-90273 in the wild and no public exploit code.

Affected product: Linux. 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-2026-90273/ (Markdown: https://insights.sbomify.com/CVE-2026-90273/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90273
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90273
- OSV: https://osv.dev/vulnerability/CVE-2026-90273

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90273/
Summaries are generated and may contain mistakes; the official description above is the record.