KVM: guest_memfd: Treat memslot binding offset+size as unsigned values
In the Linux kernel, the following vulnerability has been resolved: KVM: guest_memfd: Treat memslot binding offset+size as unsigned values When binding a memslot to a guest_memfd file, treat the offset and size as unsigned values to fix a bug where the sum of the two can result in a false negative when checking for overflow against the size of the file. Passing unsigned values also avoids relying on somewhat obscure checks in other flows for safety, and tracks the offset and size as they are intended to be tracked, as unsigned values. On 64-bit kernels, the number of pages a memslot contains and thus the size (and offset) of its guest_memfd binding are unsigned 64-bit values. Taking the offset+size as an loff_t instead of a uoff_t inadvertently converts the unsigned value to a signed value if the offset and/or size is massive. Locally storing the offset and size as signed values is benign in and of itself (though even that is *extremely* difficult to discern), but operating on their sum is not. For the offset, KVM explicitly checks against a negative value, which might seem like a bug as KVM could incorrectly reject a legitimate binding, but that's not actually the case as KVM_CREATE_GUEST_MEMFD takes a signed value for its size, i.e. a would-be-negative offset is also greater than the maximum possible size of any guest_memfd file. Regarding the size, while KVM lacks an explicit check for a negative value, i.e. seemingly has a flawed overflow check, KVM restricts the number o
CVE-2026-64283
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64283
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "e4683654881f3303ab286e45df6f91c0675d867c",
"versionType": "git"
},
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "3f9c0fdefa0431ad7a5528d76b9cdad912500bdf",
"versionType": "git"
},
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "f3a98d5881b9bd4807f49156143565f6aabcef1e",
"versionType": "git"
},
{
"status": "affected",
"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6",
"lessThan": "eba85fee7fc6cf28fec38a5bf3c378bef9a79ca6",
"versionType": "git"
}
],
"programFiles": [
"virt/kvm/guest_memfd.c",
"virt/kvm/kvm_mm.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"virt/kvm/guest_memfd.c",
"virt/kvm/kvm_mm.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64283
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46431 · Revision 1
- Added to Heist Feed
- Publisher date