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CVE-2026-98653

KVM: s390: Fix _gaccess_shadow_fault()

CVSS score

—

EPSS probability

—

Risk score

—

Published

14 h ago

Patch status has not yet been verified

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

Linux Kernel KVM s390 Vulnerability CVE-2026-98653

Sources read

2

Source agreement

Tam uyum

Evidence confidence

%63

Short explanation

A vulnerability CVE-2026-98653 has been identified in the Linux kernel KVM s390 subsystem. Under certain circumstances, nested guest memory pages being shadowed are absent in the parent guest gmap, causing dat_entry_walk() to return -ENOENT which propagates to userspace.

Why does it matter?

This security flaw can lead to memory mapping errors propagating to userspace during nested virtualization scenarios, triggering unintended error handling.

What should be done?

  • Follow vendor advisories and updates
  • Apply updates where gmap_link() is manually invoked
Chain of evidence and sources2 verified claims

CVE-2026-98653, Linux kernel KVM s390 alt sistemindeki _gaccess_shadow_fault() fonksiyonunu etkilemektedir.

Eksik eşleme durumunda dat_entry_walk() fonksiyonu -ENOENT döndürerek hatayı kullanıcı alanına yaymaktadır.

Show the technical text from the sources

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix _gaccess_shadow_fault() In some circumstances, it is possible that the page of nested guest memory that is being shadowed is not present at all in the parent guest gmap. dat_entry_walk() will not find any leaf entry and return with -ENOENT, which will erroneously be propagated all the way to userspace. Fix by manually calling gmap_link() on the memory of the nested guest that is being shadowed if the mapping was not already present.

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-98653 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

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.

SCOREVERSIONSEVERITYVECTORSOURCE
The sources have not yet published a verified CVSS metric.

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

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-2026-98653 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-2026-98653 weaknesses.

Official Sources and Advisories

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İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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