CVE-2025-58151 varstored: TOCTOU issues with mapped guest memory

varstored is a component of the Xapi toolstack handling UEFI Variables for a VM. It has a communication path with OVMF inside the VM involving mapping a buffer prepared by OVMF. Within varstored, there were insufficient compiler barriers, creating TOCTOU issues with data in the shared buffer. The...

EUVD-2025-210447

varstored is a component of the Xapi toolstack handling UEFI Variables for a VM. It has a communication path with OVMF inside the VM involving mapping a buffer prepared by OVMF. Within varstored, there were insufficient compiler barriers, creating TOCTOU issues with data in the shared buffer. The...

CVE-2020-29487

CVE-2020-29487 affects Xen XAPI (Xen hypervisor tooling). The issue stems from xenopsd watching xenstore keys and forwarding RPC updates via message-switch to xapi, causing an RPC update flood: one update per key update with O(N^2) time, and message-switch retaining ~128 recent messages yields O(...

Hotfix XS80E006 - For Citrix Hypervisor 8.0

Who Should Install This Hotfix? This is a hotfix for customers running Citrix Hypervisor 8.0. All customers who are affected by the issues described inCTX263477 - Citrix Hypervisor Multiple Security Updatesshould install this hotfix. Ensure that you also installCTX262555 - Hotfix XS80E005 - For...