CVE-2026-80724

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).

• git.kernel.orghttps://git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc
• git.kernel.orghttps://git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11
• git.kernel.orghttps://git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d

No related CVEs by CWE or product.