# CVE-2026-72277: KVM: arm64: nv: Inject SEA if guest VNCR isn't normal memory

> A flaw in Linux KVM arm64 nested virtualization allows a guest to cause a system error and denial of service by mapping VNCR to non-memory regions.

- **Severity:** Critical 9.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72277, DEBIAN-CVE-2026-72277, GHSA-x8qc-pvh3-2vf6, UBUNTU-CVE-2026-72277

## What is CVE-2026-72277?

CVE-2026-72277 is a critical denial of service vulnerability in Linux, published on 15 Aug 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: Inject SEA if guest VNCR isn't normal memory

When constructing an L1 VNCR mapping, KVM unconditionally uses cacheable
memory attributes, even if the underlying PFN isn't memory. This gets
particularly hairy if the endpoint doesn't support cacheable memory
attributes, potentially throwing an SError on writeback...

While KVM does permit cacheable memory attributes on certain PFNMAP
VMAs, kvm_translate_vncr() isn't currently grabbing the VMA. So do the
simpler thing for now and just reject everything that isn't memory.

## Which versions are affected by CVE-2026-72277?


## How do I fix CVE-2026-72277?

Apply the vendor's patch.

## Is CVE-2026-72277 being exploited?

There is no known exploitation of CVE-2026-72277 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72277 and fix it if it is affected.

What it is: CVE-2026-72277 is a critical denial of service vulnerability in Linux, published on 15 Aug 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-2026-72277 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-2026-72277/ (Markdown: https://insights.sbomify.com/CVE-2026-72277/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72277
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72277
- OSV: https://osv.dev/vulnerability/CVE-2026-72277

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72277/
Summaries are generated and may contain mistakes; the official description above is the record.