ptp: vmclock: prevent read-only mappings from becoming writable (CVE-2026-80724) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-80724

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

Answer in brief

CVE-2026-80724 records a Unknown severity vulnerability in ptp: vmclock: prevent read-only mappings from becoming writable. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 28, 2026Updated Aug 28, 2026Source checked Aug 28, 2026First seen by HOL Aug 28, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=20503272422693d793b84f88bf23fe4e955d3a33 <5b4f2bec7bea6c04084d720d731bedee7caf878d \|\| >=20503272422693d793b84f88bf23fe4e955d3a33 <2496e141827102d6af512950057d402a2cfb2bfc \|\| >=20503272422693d793b84f88bf23fe4e955d3a33 <2e596e7814ba38cdc129991058b6c254ed37cb11	5b4f2bec7bea6c04084d720d731bedee7caf878d, 2496e141827102d6af512950057d402a2cfb2bfc, 2e596e7814ba38cdc129991058b6c254ed37cb11
Linux/Linuxgeneric	6.13	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 5b4f2bec7bea6c04084d720d731bedee7caf878d if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 28, 2026

Sources and claim methodology

Upstream source description

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).

Quoted source text, attributed separately from HOL analysis.