CVE-2026-80724

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ptp: vmclock: prevent read-only mappings from becoming writable<br /> <br /> vmclock_miscdev_mmap() rejects writable mappings of the shared vmclock<br /> ABI page with -EROFS, but leaves VM_MAYWRITE set. Userspace can map the<br /> page read-only and then upgrade it to writable with mprotect(), after<br /> which the guest can corrupt the host-written timekeeping data (sequence<br /> counter, UTC time, TSC offset) that the vmclock ABI defines as read-only.<br /> <br /> Clear VM_MAYWRITE on the read-only path so the mapping cannot be<br /> upgraded, as i915 does for its read-only objects and as fixed in drm/vc4<br /> (CVE-2026-68445) and drm/panthor (CVE-2024-53071).