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).
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Public exploits 1
- suruurism/cve-writeups-and-pocs PoC on GitHub
Each line links to the index that lists it, never to exploit code. Exploit-DB's "verified" and a Metasploit rank of good or better count as verified; a PoC-in-GitHub entry is a repository's claim.
Change history 2
- StatusReceived → PublishedNVD modified 2026-10-19 08:43
- First seenCVSS 8.8NVD modified 2026-10-19 09:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 6
- https://git.kernel.org/stable/c/0ce59c4148ecd1520c5592a63bb3c8991ee2d326
- https://git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc
- https://git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11
- https://git.kernel.org/stable/c/3f5677d2f817355147337f0453174c7bb0f3b66a
- https://git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d
- https://git.kernel.org/stable/c/a5edadbae57e2298a56cf7a4e774a027905a331f