{"id":"CVE-2026-80724","summary":"ptp: vmclock: prevent read-only mappings from becoming writable","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nptp: vmclock: prevent read-only mappings from becoming writable\n\nvmclock_miscdev_mmap() rejects writable mappings of the shared vmclock\nABI page with -EROFS, but leaves VM_MAYWRITE set.  Userspace can map the\npage read-only and then upgrade it to writable with mprotect(), after\nwhich the guest can corrupt the host-written timekeeping data (sequence\ncounter, UTC time, TSC offset) that the vmclock ABI defines as read-only.\n\nClear VM_MAYWRITE on the read-only path so the mapping cannot be\nupgraded, as i915 does for its read-only objects and as fixed in drm/vc4\n(CVE-2026-68445) and drm/panthor (CVE-2024-53071).","modified":"2026-08-29T03:47:17.235580538Z","published":"2026-08-28T07:03:08.410Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80724.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80724.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80724"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"20503272422693d793b84f88bf23fe4e955d3a33"},{"fixed":"5b4f2bec7bea6c04084d720d731bedee7caf878d"},{"fixed":"2496e141827102d6af512950057d402a2cfb2bfc"},{"fixed":"2e596e7814ba38cdc129991058b6c254ed37cb11"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80724.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.47"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.2.0"},{"fixed":"7.2.1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80724.json"}}],"schema_version":"1.9.0"}