# CVE-2026-0665: Qemu-kvm: heap off-by-one in kvm xen physdevop_map_pirq

> A malicious guest can trigger heap out-of-bounds access in QEMU via Xen hypercalls, causing denial of service or potential code execution.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:L/AC:L/PR:L/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 Feb 2026
- **Updated:** 18 Feb 2026
- **Also known as:** BELL-CVE-2026-0665, DEBIAN-CVE-2026-0665, GHSA-4pq4-6gr5-cr69, OESA-2026-1352, SUSE-SU-2026:0445-1, UBUNTU-CVE-2026-0665, openSUSE-SU-2026:10097-1

## What is CVE-2026-0665?

CVE-2026-0665 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 18 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An off-by-one error was found in QEMU's KVM Xen guest support. A malicious guest could use this flaw to trigger out-of-bounds heap accesses in the QEMU process via the emulated Xen physdev hypercall interface, leading to a denial of service or potential memory corruption.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-0665?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `qemu` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 9.2.4-150700.3.14.1 |
| `qemu` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 9.2.4-150700.3.14.1 |
| `qemu-linux-user` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 9.2.4-150700.3.14.1 |
| `qemu` | SUSE:Linux Enterprise Module for Server Applications 15 SP7 | All versions | 9.2.4-150700.3.14.1 |
| `qemu` | openSUSE:Tumbleweed | All versions | 10.2.0-2.1 |

## How do I fix CVE-2026-0665?

Apply the vendor's patch.

## Is CVE-2026-0665 being exploited?

There is no known exploitation of CVE-2026-0665 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-0665 and fix it if it is affected.

What it is: CVE-2026-0665 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 18 Feb 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-2026-0665 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2026-0665/ (Markdown: https://insights.sbomify.com/CVE-2026-0665/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-0665
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-0665
- OSV: https://osv.dev/vulnerability/CVE-2026-0665

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-0665/
Summaries are generated and may contain mistakes; the official description above is the record.