VulnerabilityPublished 15 Aug 2026Updated 9 Oct 2026

CVE-2026-72292: Linux kernel · KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory

Affects Linux kernelSource GCVE Database

Not known to be exploited · fixed in 7.0.0-1014.14~24.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.0-1014.14~24.04.1, 7.0.0-1017.17~24.04.1, 7.0.0-1016.16~24.04.1 +11

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Aug 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-g39r-65h4-wx32

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected <7.0.0-38.38	Fixed in 7.0.0-38.38
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected <7.0.0-1017.17	Fixed in 7.0.0-1017.17
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected <7.0.0-1016.16	Fixed in 7.0.0-1016.16
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected <7.0.0-1008.9	Fixed in 7.0.0-1008.9

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 that fixes this vulnerability by changing the buffer allocation to zero-initialize memory using vzalloc(). Users should apply the official Linux kernel updates that address CVE-2026-72292. The vendor advisory confirms that this issue has been resolved. No additional mitigation steps are required beyond applying the update.

Description

A vulnerability in the Linux kernel's KVM s390 subsystem causes uninitialized kernel memory to be disclosed to user space. The function kvm_s390_get_cmma_bits() allocates an output buffer without zeroing it, leading to stale kernel memory exposure during certain memory migration operations. This issue was introduced after switching to a new gmap implementation that performs a dirty-only walk, leaving gaps in the buffer uninitialized. The vulnerability has been fixed by changing the allocation to zero-initialize the buffer.

Impact

This vulnerability allows disclosure of stale kernel memory to user space processes during KVM s390 memory migration operations. Such leakage could expose sensitive kernel data, potentially aiding an attacker with access to the affected subsystem. There are no known exploits in the wild. The impact is limited to information disclosure rather than code execution or privilege escalation.

Summary

The Linux kernel's KVM s390 subsystem had a vulnerability (CVE-2026-72292) where the function kvm_s390_get_cmma_bits() allocated its output buffer using vmalloc(), which does not zero the allocated memory. During the non-peek (migration) path, the function dat_get_cmma() reports a byte count spanning from the first to the last dirty page, but only pages with the CMMA dirty bit set are written to the buffer. Clean and unmapped pages between dirty pages remain uninitialized, causing stale kernel memory to be copied to user space via copy_to_user(). Previously, the buffer was fully populated, so no uninitialized bytes were exposed. The fix involved using vzalloc() to zero-initialize the buffer, preventing leakage of stale kernel memory.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 07:56 UTC

Technical details

References

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