CVE-2026-80724 ptp: vmclock: prevent read-only mappings from becoming writable
A guest user can escalate privileges by modifying read-only vmclock data via mprotect, requiring kernel patching.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80724?
CVE-2026-80724 is a high-severity vulnerability in Linux, published on 28 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:
ptp: vmclock: prevent read-only mappings from becoming writable
vmclock_miscdev_mmap() rejects writable mappings of the shared vmclock ABI page with -EROFS, but leaves VM_MAYWRITE set. Userspace can map the page read-only and then upgrade it to writable with mprotect(), after which the guest can corrupt the host-written timekeeping data (sequence counter, UTC time, TSC offset) that the vmclock ABI defines as read-only.
Clear VM_MAYWRITE on the read-only path so the mapping cannot be upgraded, as i915 does for its read-only objects and as fixed in drm/vc4 (CVE-2026-68445) and drm/panthor (CVE-2024-53071).
Which versions are affected by CVE-2026-80724?
Linux distribution packages (1)
kernel-source openSUSE:Tumbleweed | All versions | 7.2.3-1.1 |
How do I fix CVE-2026-80724?
Apply the vendor's patch.
Is CVE-2026-80724 being exploited?
There is no known exploitation of CVE-2026-80724 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as BELL-CVE-2026-80724, DEBIAN-CVE-2026-80724, GHSA-66mv-wq2c-77c3, UBUNTU-CVE-2026-80724, openSUSE-SU-2026:11703-1.