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CVE-2026-80724

ptp: vmclock: prevent read-only mappings from becoming writable PUBLISHED

Description (CNA)

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).

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 20503272422693d793b84f88bf23fe4e955d3a33 before 5b4f2bec7bea6c04084d720d731bedee7caf878d; affected 20503272422693d793b84f88bf23fe4e955d3a33 before 3f5677d2f817355147337f0453174c7bb0f3b66a; affected 20503272422693d793b84f88bf23fe4e955d3a33 before 2496e141827102d6af512950057d402a2cfb2bfc; affected 20503272422693d793b84f88bf23fe4e955d3a33 before 2e596e7814ba38cdc129991058b6c254ed37cb11; affected 20503272422693d793b84f88bf23fe4e955d3a33 before 0ce59c4148ecd1520c5592a63bb3c8991ee2d326; affected 20503272422693d793b84f88bf23fe4e955d3a33 before a5edadbae57e2298a56cf7a4e774a027905a331f
Linux / Linuxaffected 6.13; unaffected 0 before 6.13; unaffected 6.18.47 through 6.18.*; unaffected 6.18.50 through 6.18.*; unaffected 7.1.11 through 7.1.*; unaffected 7.2.1 through 7.2.*; unaffected 7.2.4 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References