ptp: vmclock: prevent read-only mappings from becoming writable
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
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).
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.18.47, 6.18.50, 7.1.11, 7.2.1, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-80724
- 2026-10-03 Alias added: GHSA-66mv-wq2c-77c3
- 2026-10-19 Fix available: Linux/[email protected] · CNA
References
Other 6
- https://git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d
- https://git.kernel.org/stable/c/3f5677d2f817355147337f0453174c7bb0f3b66a
- https://git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc
- https://git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11
- https://git.kernel.org/stable/c/0ce59c4148ecd1520c5592a63bb3c8991ee2d326
- https://git.kernel.org/stable/c/a5edadbae57e2298a56cf7a4e774a027905a331f
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Sources
- CVE-2026-80724 · CVE Program
- CVE-2026-80724 · NVD
- FIRST EPSS
- GHSA-66mv-wq2c-77c3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-80724 · Red Hat security data · CC BY 4.0
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