VulnerabilityPublished 24 Apr 2026Updated 21 Oct 2026

CVE-2026-31568: Linux kernel · s390/mm: Add missing secure storage access fixups for donated memory

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

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 b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88, b00be77302d7ec4ad0367bb236494fce7172b730, 74ccc099f1baa9236b8fb600406457a0870c83a9 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Apr 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 to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 084ea4d611a3d00ee3930400b262240e10895900, < b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88	Fixed in b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88
LinuxLinux	Affected ≥ 084ea4d611a3d00ee3930400b262240e10895900, < b00be77302d7ec4ad0367bb236494fce7172b730	Fixed in b00be77302d7ec4ad0367bb236494fce7172b730
LinuxLinux	Affected ≥ 084ea4d611a3d00ee3930400b262240e10895900, < 74ccc099f1baa9236b8fb600406457a0870c83a9	Fixed in 74ccc099f1baa9236b8fb600406457a0870c83a9
LinuxLinux	Affected ≥ 084ea4d611a3d00ee3930400b262240e10895900, < 43ac2d18db1131df0a89993f709131ebfc29f3bd	Fixed in 43ac2d18db1131df0a89993f709131ebfc29f3bd
LinuxLinux	Affected ≥ 084ea4d611a3d00ee3930400b262240e10895900, < 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd	Fixed in 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd
LinuxLinux	Affected =5.7	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: s390/mm: Add missing secure storage access fixups for donated memory There are special cases where secure storage access exceptions happen in a kernel context for pages that don't have the PG_arch_1 bit set. That bit is set for non-exported guest secure storage (memory) but is absent on storage donated to the Ultravisor since the kernel isn't allowed to export donated pages. Prior to this patch we would try to export the page by calling arch_make_folio_accessible() which would instantly return since the arch bit is absent signifying that the page was already exported and no further action is necessary. This leads to secure storage access exception loops which can never be resolved. With this patch we unconditionally try to export and if that fails we fixup.

References

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