VulnerabilityPublished 18 Oct 2026

CVE-2026-98650: Linux kernel · KVM: s390: Fix potential races in dat skey functions

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to c958f0498891203fddf2764b28f8b102c6bfd719 or 27554b9505ddfc0aeab466aeb60929dfa17284c7 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · 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 c958f0498891203fddf2764b28f8b102c6bfd719, 27554b9505ddfc0aeab466aeb60929dfa17284c7

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.

What to do

Upgrade Linux kernel to c958f0498891203fddf2764b28f8b102c6bfd719 or 27554b9505ddfc0aeab466aeb60929dfa17284c7.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 8e03e8316eb242af307d1c789d09f1a1457cf9a3, < c958f0498891203fddf2764b28f8b102c6bfd719	Fixed in c958f0498891203fddf2764b28f8b102c6bfd719
LinuxLinux	Affected ≥ 8e03e8316eb242af307d1c789d09f1a1457cf9a3, < 27554b9505ddfc0aeab466aeb60929dfa17284c7	Fixed in 27554b9505ddfc0aeab466aeb60929dfa17284c7
LinuxLinux	Affected =7.0	Fixed in–
Debiandebian/linux`pkg:deb/debian/linux`Other threats	Affected =7.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been applied in the specified commits. Users should update to the fixed Linux kernel versions containing these commits to remediate the issue. Since this is a kernel-level race condition, applying the official fix is the recommended mitigation.

Description

A race condition vulnerability in the Linux kernel's KVM s390 architecture was fixed. The issue involved potential concurrent splitting of large pages during storage key operations, which could lead to crashes. The flaw was addressed by changing how the crste pointer is accessed to avoid unsafe dereferencing during races.

Impact

The vulnerability could cause kernel crashes due to unsafe memory access during concurrent large page splits in the s390 KVM dat skey functions. There is no indication of code execution or privilege escalation. No known exploits in the wild have been reported.

Summary

CVE-2026-98650 describes a race condition in the Linux kernel's KVM s390 implementation affecting dat skey functions. Specifically, dat_cond_set_storage_key() and dat_set_storage_key() could dereference a crste pointer after a large page was concurrently split, causing crashes. The functions dat_get_storage_key() and dat_reset_reference_bit() checked for concurrent splits but handled them incorrectly. The fix involves using READ_ONCE on the crste pointer to safely check and use it, retrying dat_entry_walk() if a race is detected. This vulnerability was fixed in commits c958f0498891203fddf2764b28f8b102c6bfd719 and 27554b9505ddfc0aeab466aeb60929dfa17284c7.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:04 UTC

Technical details

References

Community reviews

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