---
id: CVE-2026-102703
title: arbitrary read/write via grant copy
summary: |-
  [This CNA information record relates to multiple CVEs; the
  text explains which aspects/vulnerabilities correspond to which CVE.]

  A common access pattern is a batch of Grant Copy operations acting on
  adjacent address ranges in the same s…
severity: medium
cvss: 4.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'
cvssSource: adp
vendor: Xen
product: Xen
affected:
  - Xen
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-04T18:24:51.875183Z'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T18:24:55.422Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-102703'
references:
  - url: 'https://xenbits.xenproject.org/xsa/advisory-523.html'
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.486Z'
epss: 0.00143
epssPercentile: 0.03647
---

## Overview

[This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]

A common access pattern is a batch of Grant Copy operations acting on
adjacent address ranges in the same source or destination page.  For
performance reasons, Xen caches details internally to reuse already
validated data.  The conditions on when to re-validate the internal data
were not correct in some cases:

 - Frame numbers and grant references could wrongly be mixed up.  This
   is CVE-2026-102703.

 - Copying by frame number (rather than grant reference) is permitted
   only when operating on the caller's own memory.  The check to enforce
   this restriction was misplaced.  This is CVE-2026-102704.

## Affected

- `Xen`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

There is no known mitigation.