CVE-2026-31590 (GCVE-0-2026-31590)
Vulnerability from cvelistv5 – Published: 2026-04-24 14:42 – Updated: 2026-04-27 13:56
VLAI?
Title
KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION
Drop the WARN in sev_pin_memory() on npages overflowing an int, as the
WARN is comically trivially to trigger from userspace, e.g. by doing:
struct kvm_enc_region range = {
.addr = 0,
.size = -1ul,
};
__vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
Note, the checks in sev_mem_enc_register_region() that presumably exist to
verify the incoming address+size are completely worthless, as both "addr"
and "size" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater
than ULONG_MAX. That wart will be cleaned up in the near future.
if (range->addr > ULONG_MAX || range->size > ULONG_MAX)
return -EINVAL;
Opportunistically add a comment to explain why the code calculates the
number of pages the "hard" way, e.g. instead of just shifting @ulen.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < b670833749ffd8681361db2bb047c6f2e3075f3a
(git)
Affected: 78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < ab423e5892826202a660b5ac85d1125b0e8301a5 (git) Affected: 78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < 28cc13ca20431b127d42d84ba10898d03e2c8267 (git) Affected: 78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < c29ff288a2d97a6f4640a498a367cf0eb91312eb (git) Affected: 78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < 1cba4dcd795daf6d257122779fb6a349edf03914 (git) Affected: 78824fabc72e5e37d51e6e567fde70a4fc41a6d7 , < 8acffeef5ef720c35e513e322ab08e32683f32f2 (git) |
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{
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION\n\nDrop the WARN in sev_pin_memory() on npages overflowing an int, as the\nWARN is comically trivially to trigger from userspace, e.g. by doing:\n\n struct kvm_enc_region range = {\n .addr = 0,\n .size = -1ul,\n };\n\n __vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, \u0026range);\n\nNote, the checks in sev_mem_enc_register_region() that presumably exist to\nverify the incoming address+size are completely worthless, as both \"addr\"\nand \"size\" are u64s and SEV is 64-bit only, i.e. they _can\u0027t_ be greater\nthan ULONG_MAX. That wart will be cleaned up in the near future.\n\n\tif (range-\u003eaddr \u003e ULONG_MAX || range-\u003esize \u003e ULONG_MAX)\n\t\treturn -EINVAL;\n\nOpportunistically add a comment to explain why the code calculates the\nnumber of pages the \"hard\" way, e.g. instead of just shifting @ulen."
}
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"url": "https://git.kernel.org/stable/c/1cba4dcd795daf6d257122779fb6a349edf03914"
},
{
"url": "https://git.kernel.org/stable/c/8acffeef5ef720c35e513e322ab08e32683f32f2"
}
],
"title": "KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION",
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"datePublished": "2026-04-24T14:42:17.629Z",
"dateReserved": "2026-03-09T15:48:24.120Z",
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"date": "2026-05-05",
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}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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