# CVE-2026-98469: KVM: arm64: Fix AArch32 DBGBXVR<n> handling

> A guest VM can crash the host kernel by accessing specific debug registers, causing a denial of service.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/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:** 18 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** BELL-CVE-2026-98469, DEBIAN-CVE-2026-98469, GHSA-vcw8-qqhm-h682, UBUNTU-CVE-2026-98469

## What is CVE-2026-98469?

CVE-2026-98469 is a high-severity denial of service vulnerability in Linux, published on 18 Oct 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: Fix AArch32 DBGBXVR<n> handling

The consolidation of the breakpoint and watchpoint register accessors
switched DBGBXVR<n> from trap_bvr() to trap_dbg_wb_reg(). The latter
selects backing storage with demux_wb_reg(), which only handles Op2 values
4 through 7. Since DBGBXVR<n> uses Op2 1, an AArch32 guest access hits
KVM_BUG_ON() and marks the VM dead.

DBGBXVR<n> aliases DBGBVR<n>_EL1[63:32], and its AA32(HI) descriptor
already selects the upper half. Map Op2 1 to dbg_bvr[] alongside Op2 4,
restoring the pre-regression behavior.

## Which versions are affected by CVE-2026-98469?


## How do I fix CVE-2026-98469?

Apply the vendor's patch.

## Is CVE-2026-98469 being exploited?

There is no known exploitation of CVE-2026-98469 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98469 and fix it if it is affected.

What it is: CVE-2026-98469 is a high-severity denial of service vulnerability in Linux, published on 18 Oct 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-2026-98469 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-2026-98469/ (Markdown: https://insights.sbomify.com/CVE-2026-98469/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98469
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98469
- OSV: https://osv.dev/vulnerability/CVE-2026-98469

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98469/
Summaries are generated and may contain mistakes; the official description above is the record.