# CVE-2026-62428: grant-table: type confusion in grant-copy

> A race condition in Xen's grant-copy allows attackers to bypass permission checks, potentially leading to privilege escalation or unauthorized data access.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/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:** 28 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** ALPINE-CVE-2026-62428, DEBIAN-CVE-2026-62428, GHSA-qmxg-rhxf-8273, UBUNTU-CVE-2026-62428

## What is CVE-2026-62428?

CVE-2026-62428 is a high-severity vulnerability in Xen, published on 28 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

When grant-copy operations are processed, the respective grant may or may
not already be in use by another operation (a mapping or another copy).
For all copy operations the referenced guest frame is looked up.  When
another operation is already active for the grant (the grant is "pinned"),
what is being supplied back to actually carry out permission checks and
copy operation may not be consistent: The permission check may be carried
out on a page different from the one involved in the copy.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-62428?


## How do I fix CVE-2026-62428?

Apply the vendor's patch.

## Is CVE-2026-62428 being exploited?

There is no known exploitation of CVE-2026-62428 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62428 and fix it if it is affected.

What it is: CVE-2026-62428 is a high-severity vulnerability in Xen, published on 28 Jul 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-2026-62428 in the wild and no public exploit code.

Affected product: Xen. 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-2026-62428/ (Markdown: https://insights.sbomify.com/CVE-2026-62428/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62428
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62428
- OSV: https://osv.dev/vulnerability/CVE-2026-62428

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62428/
Summaries are generated and may contain mistakes; the official description above is the record.