Quick answers
- Is CVE-2026-102703 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-102703 being exploited in the wild.
- How severe is CVE-2026-102703?
- Informational severity, published 4 November 2026.
- Which products and versions are affected?
- Xen Project Xen 4.6 through 4.19.x.
- Is there a fix for CVE-2026-102703?
- Yes: fixed in Patches for Xen 4.19.x, 4.18.x, and 4.17.x available; stable branches should be updated before applying patches. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-102703 attacked?
- It is attacked with local access, in an operating system.
- Am I affected by CVE-2026-102703?
- Check whether you run Xen Project Xen at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: Patches for Xen 4.19.x, 4.18.x, and 4.17.x available; stable branches should be updated before applying patches
Technical details
A performance optimization in Xen's grant copy operations caches validation details for adjacent memory ranges. The cache invalidation logic incorrectly allows frame numbers and grant references to be mixed up, and the permission check for frame-number-based copying (which should only work on the caller's own memory) is misplaced. An attacker in a guest domain can exploit this to read and write memory of other domains via craft Grant Copy operations.
Affected products
- Xen Project Xen 4.6 through 4.19.x
Timeline
- 2026-11-03: disclosed
- 2026-11-04: advisory