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.

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History

Sat, 25 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-190
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 24 Apr 2026 15:00:00 +0000

Type Values Removed Values Added
Description 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.
Title KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-04-24T14:42:17.629Z

Reserved: 2026-03-09T15:48:24.120Z

Link: CVE-2026-31590

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-04-24T15:16:36.170

Modified: 2026-04-24T17:51:40.810

Link: CVE-2026-31590

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-24T00:00:00Z

Links: CVE-2026-31590 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses