I've been auditing hypervisor kernel security in several regulated environments recently, focusing on post-compromise survivability rather than initial breach prevention.

One pattern keeps showing up: most hardening guidance focuses on management planes and guest OSes, but real-world escape chains increasingly pivot through the host kernel (Ring 0).

From recent CVEs (ESXi heap overflows, vmx_exit handler bugs, etc.), three primitives appear consistently in successful guest → host escapes:

1. Unsigned drivers / DKOM
   If an attacker can load a third-party module, they often bypass scheduler controls entirely. Many environments still relax signature enforcement for compatibility with legacy agents, which effectively enables kernel write primitives.

2. Memory corruption vs. KASLR
   KASLR is widely relied on, but without strict kernel lockdown, leaking the kernel base address is often trivial via side channels. Once offsets are known, KASLR loses most of its defensive value.

3. Kernel write primitives
   HVCI/VBS or equivalent kernel integrity enforcement introduces measurable performance overhead (we saw ~12–18% CPU impact in some workloads), but appears to be one of the few effective controls against kernel write primitives once shared memory is compromised.

I’m curious what others are seeing in production:

• Are you enforcing strict kernel lockdown / signed modules on hypervisors?

• Are driver compatibility or performance constraints forcing exceptions?

• Have you observed real-world guest → host escapes that weren’t rooted in kernel memory corruption or unsigned drivers?

Looking to compare field experiences rather than promote any particular stack.