CVE-2026-72279 KVM: arm64: nv: Respect read-only PFN when mapping L1 VNCR
A flaw in Linux KVM arm64 nested virtualization allows guest writes to read-only memory, potentially enabling privilege escalation or data modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72279?
CVE-2026-72279 is a critical vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Respect read-only PFN when mapping L1 VNCR
KVM currently maps the L1 VNCR into the host stage-1 by relying entirely on the permissions of the guest stage-1. At the same time, it is entirely possible that the backing PFN is read-only (e.g. RO memslot), meaning that the L1 VNCR should use at most a read-only mapping.
Cache the writability of the PFN in the VNCR TLB and use it to constrain the resulting fixmap permissions. Promote VNCR permission faults to an SEA in the case where the guest attempts to write to a read-only endpoint. Conveniently, this also plugs a page leak found by Sashiko [*] resulting from the early return for a read-only PFN.
Which versions are affected by CVE-2026-72279?
How do I fix CVE-2026-72279?
Apply the vendor's patch.
Is CVE-2026-72279 being exploited?
There is no known exploitation of CVE-2026-72279 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72279, DEBIAN-CVE-2026-72279, GHSA-3627-jjwg-8vfw, UBUNTU-CVE-2026-72279.