Vulnerability in Xen

[ Description ]Official description

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] 1) XSA-437 (CVE-2023-34321) addressed issues with overflows in calculations involved in guests flushing caches through GNTTABOP_cache_flush. Unfortunately the fix there introduced a calculation which may underflow, resulting in a loop which would - at least on 64-bit Arm - take excessively long, and which would likely eventually crash the hypervisor. This is CVE-2026-102699. 2) GNTTABOP_cache_flush may be issued on memory mapped from another domain using the grant table interface. However there was no restriction to disallow the use of invalidate-without-clean against read-only grant mappings, which may corrupt the granted memory. This is CVE-2026-102702.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• CERT-FR14 Oct 2026CERTFR-2026-AVI-1302

  Multiple vulnerabilities in Xen Translated from French

  Multiple vulnerabilities have been discovered in Xen. Some of them allow an attacker to cause arbitrary code execution, privilege escalation and a breach of data confidentiality.

  CVE-2026-79611CVE-2023-34321CVE-2026-102700+10 more CVEs
• BSI CERT-Bund13 Oct 2026WID-SEC-2026-3930

  Xen: Multiple vulnerabilities Translated from German

  CVE-2026-102701CVE-2026-79610CVE-2026-102700+6 more CVEs

[ References ]References

• xenbits.xenproject.org/xsa/advisory-519.html