# CVE-2026-80873: KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions

> A guest L2 hypervisor can read stale ESR_EL2 values due to missing syndrome writes for nested SError exceptions in the Linux kernel KVM module.

- **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:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** BELL-CVE-2026-80873, DEBIAN-CVE-2026-80873, GHSA-hw7g-293v-4f3g, UBUNTU-CVE-2026-80873

## What is CVE-2026-80873?

CVE-2026-80873 is a vulnerability in Linux, published on 4 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:

KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions

kvm_inject_el2_exception() writes ESR_EL2 for synchronous exceptions
but not for SError. enter_exception64() does not write ESR_ELx for any
exception type, so the constructed syndrome is dropped. A guest L2
hypervisor taking a nested SError observes stale ESR_EL2.

This affects both kvm_inject_nested_serror() and the EASE path in
kvm_inject_nested_sea().

Write ESR_EL2 for except_type_serror, matching except_type_sync.

## Which versions are affected by CVE-2026-80873?


## How do I fix CVE-2026-80873?

Apply the vendor's patch.

## Is CVE-2026-80873 being exploited?

There is no known exploitation of CVE-2026-80873 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80873 and fix it if it is affected.

What it is: CVE-2026-80873 is a vulnerability in Linux, published on 4 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-2026-80873 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-2026-80873/ (Markdown: https://insights.sbomify.com/CVE-2026-80873/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80873
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80873
- OSV: https://osv.dev/vulnerability/CVE-2026-80873

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80873/
Summaries are generated and may contain mistakes; the official description above is the record.