# CVE-2026-90121: irqchip/gic-v5: Clear per-CPU IRS data on teardown

> A use-after-free vulnerability in the Linux kernel GIC-v5 driver allows local attackers to execute arbitrary code or escalate privileges via stale per-CPU pointers.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90121, DEBIAN-CVE-2026-90121, GHSA-fx3f-7rrv-pccf, UBUNTU-CVE-2026-90121

## What is CVE-2026-90121?

CVE-2026-90121 is an use after free 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:

irqchip/gic-v5: Clear per-CPU IRS data on teardown

IRS affinity setup publishes an IRS pointer and IAFFID state in the
per-CPU data before the remaining IRS initialization can fail. The
error path then frees the IRS data without clearing that published
state, leaving CPUs associated with freed memory.

On initialization failure and normal IRS teardown, clear the per-CPU
IRS association by removing the stale pointer to irs_data. Also
invalidate the per-CPU IAFFID state for any CPUs that were tied to the
IRS before it was freed.

## Which versions are affected by CVE-2026-90121?


## How do I fix CVE-2026-90121?

Apply the vendor's patch.

## Is CVE-2026-90121 being exploited?

There is no known exploitation of CVE-2026-90121 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90121 and fix it if it is affected.

What it is: CVE-2026-90121 is an use after free 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-2026-90121 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-2026-90121/ (Markdown: https://insights.sbomify.com/CVE-2026-90121/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90121
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90121
- OSV: https://osv.dev/vulnerability/CVE-2026-90121

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90121/
Summaries are generated and may contain mistakes; the official description above is the record.