VulnerabilityPublished 18 Oct 2026

CVE-2026-98653: Linux kernel · KVM: s390: Fix _gaccess_shadow_fault()

Source GCVE Database

Authoritative record:CVE-2026-98653

Not known to be exploited : upgrade to faff4c8ff3dbec6d71b89dd281a0d17c4478fa44 or 94c43c7df46433ed4d1e18f13770b019ba977bd8 when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in faff4c8ff3dbec6d71b89dd281a0d17c4478fa44, 94c43c7df46433ed4d1e18f13770b019ba977bd8

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-v97x-654r-4f82

What to do

Upgrade Linux kernel to faff4c8ff3dbec6d71b89dd281a0d17c4478fa44 or 94c43c7df46433ed4d1e18f13770b019ba977bd8.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ e38c884df92119d96f652d51f82661dd2fc0b885, < faff4c8ff3dbec6d71b89dd281a0d17c4478fa44	Fixed in faff4c8ff3dbec6d71b89dd281a0d17c4478fa44
LinuxLinux	Affected ≥ e38c884df92119d96f652d51f82661dd2fc0b885, < 94c43c7df46433ed4d1e18f13770b019ba977bd8	Fixed in 94c43c7df46433ed4d1e18f13770b019ba977bd8
LinuxLinux	Affected =7.0	Fixed in–

AI-suggested

A fix has been implemented to address this vulnerability by modifying the _gaccess_shadow_fault() function to manually call gmap_link() when necessary. Users should apply the official Linux kernel patch that resolves this issue. Since this is a kernel-level fix, updating to the patched kernel version is the recommended remediation.

Description

A vulnerability in the Linux kernel's KVM s390 subsystem related to the _gaccess_shadow_fault() function has been resolved. The issue occurs when a nested guest memory page being shadowed is not present in the parent guest gmap, causing dat_entry_walk() to fail and erroneously propagate an error to userspace. The fix involves manually calling gmap_link() on the nested guest memory if the mapping was missing.

References

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