ptp: vmclock: prevent read-only mappings from becoming writable
CVSS score
8.8
EPSS probability
%0.2
Risk score
0.0
Published
1 mo ago
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
Tam uyum
Evidence confidence
%61
Short explanation
CVE-2026-80724 is a high-severity vulnerability in the Linux kernel's ptp vmclock module allowing userspace to upgrade read-only mappings to writable ones via mprotect(), enabling guest-side corruption of host timekeeping data. Patch status is UNKNOWN due to lack of reliable evidence in official sources.
Timekeeping data corruption can disrupt system synchronization, affect distributed services, and compromise security mechanisms relying on accurate time. This vulnerability impacts systems using virtualization with precise timekeeping requirements.
What should be done?
- Apply official kernel updates that include the fix for vmclock_miscdev_mmap() to clear VM_MAYWRITE on read-only mappings
- Follow vendor advisories for specific version ranges
The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.
Chain of evidence and sources
CVE-2026-80724, Linux çekirdeğinin ptp vmclock modülüne ait yüksek tehditli bir açıklık, kullanıcı alanından okunabilir olmayan eşleme yapılarını mprotect() ile yazılabilir hale getirmesini sağlar ve bu sayede sanal makinelerin ana bilgisayar tarafından yazılan zaman bilgilerini (dizi sayacı, UTC zamanı, TSC offset) bozmasına neden olur.
Açıklık, 6.13 sürümünden önceki belirli Linux çekirdeği sürümlerine aittir ve bu sürüm aralıkları kriptografik hash değerlerle tanımlanır. vmclock_miscdev_mmap() fonksiyonunda okunabilir olmayan eşlemlerde VM_MAYWRITE'nin kaldırılmasıyla giderilir.
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Show the technical text from the sources
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).
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Explanation produced with the local qwen3:4b-instruct model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 8.8 | CVSS V3_1 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | CVE CNA |
| 8.8 | CVSS V31 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-80724 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-80724 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
8.8 / 10Vulnerability Scoring Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HYama durumu bilinmiyor
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