CVE-2026-102699

[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.