CVE-2026-72292 (GCVE-0-2026-72292)
Vulnerability from cvelistv5
Published
2026-08-15 05:55
Modified
2026-08-17 05:11
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory
kvm_s390_get_cmma_bits() allocates its output buffer with vmalloc(),
which does not zero the returned pages:
values = vmalloc(args->count);
In the non-peek (migration) path, dat_get_cmma() reports a byte count
spanning from the first to the last dirty page, but __dat_get_cmma_pte()
writes values[gfn - start] only for pages whose CMMA dirty bit is set.
The walk uses DAT_WALK_IGN_HOLES, so clean and unmapped pages that lie
between two dirty pages within the reported span are visited but never
store their byte. Those gaps (up to KVM_S390_MAX_BIT_DISTANCE pages
each) stay uninitialized yet fall inside [0, count) and are copied out
by copy_to_user(), disclosing stale kernel memory to user space.
Before the switch to the new gmap implementation the buffer was fully
populated for every gfn in the span, so no uninitialized bytes were
exposed; the dirty-only walk introduced the leak.
Use vzalloc() so the gaps read back as zero.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/s390/kvm/kvm-s390.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "a4a19941ccb2164edc3491faa5ac5df82e94b363",
"status": "affected",
"version": "e38c884df92119d96f652d51f82661dd2fc0b885",
"versionType": "git"
},
{
"lessThan": "c7dda3d0f869dc97223448a06c9a2e5235928e48",
"status": "affected",
"version": "e38c884df92119d96f652d51f82661dd2fc0b885",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/s390/kvm/kvm-s390.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
"lessThan": "7.0",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "7.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "7.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory\n\nkvm_s390_get_cmma_bits() allocates its output buffer with vmalloc(),\nwhich does not zero the returned pages:\n\n\tvalues = vmalloc(args-\u003ecount);\n\nIn the non-peek (migration) path, dat_get_cmma() reports a byte count\nspanning from the first to the last dirty page, but __dat_get_cmma_pte()\nwrites values[gfn - start] only for pages whose CMMA dirty bit is set.\nThe walk uses DAT_WALK_IGN_HOLES, so clean and unmapped pages that lie\nbetween two dirty pages within the reported span are visited but never\nstore their byte. Those gaps (up to KVM_S390_MAX_BIT_DISTANCE pages\neach) stay uninitialized yet fall inside [0, count) and are copied out\nby copy_to_user(), disclosing stale kernel memory to user space.\n\nBefore the switch to the new gmap implementation the buffer was fully\npopulated for every gfn in the span, so no uninitialized bytes were\nexposed; the dirty-only walk introduced the leak.\n\nUse vzalloc() so the gaps read back as zero."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:11:54.937Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/a4a19941ccb2164edc3491faa5ac5df82e94b363"
},
{
"url": "https://git.kernel.org/stable/c/c7dda3d0f869dc97223448a06c9a2e5235928e48"
}
],
"title": "KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72292",
"datePublished": "2026-08-15T05:55:13.248Z",
"dateReserved": "2026-08-09T03:40:39.917Z",
"dateUpdated": "2026-08-17T05:11:54.937Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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