KVM: Don't clobber irqfd routing type when deassigning irqfd
In the Linux kernel, the following vulnerability has been resolved: KVM: Don't clobber irqfd routing type when deassigning irqfd When deassigning a KVM_IRQFD, don't clobber the irqfd's copy of the IRQ's routing entry as doing so breaks kvm_arch_irq_bypass_del_producer() on x86 and arm64, which explicitly look for KVM_IRQ_ROUTING_MSI. Instead, to handle a concurrent routing update, verify that the irqfd is still active before consuming the routing information. As evidenced by the x86 and arm64 bugs, and another bug in kvm_arch_update_irqfd_routing() (see below), clobbering the entry type without notifying arch code is surprising and error prone. As a bonus, checking that the irqfd is active provides a convenient location for documenting _why_ KVM must not consume the routing entry for an irqfd that is in the process of being deassigned: once the irqfd is deleted from the list (which happens *before* the eventfd is detached), it will no longer receive updates via kvm_irq_routing_update(), and so KVM could deliver an event using stale routing information (relative to KVM_SET_GSI_ROUTING returning to userspace). As an even better bonus, explicitly checking for the irqfd being active fixes a similar bug to the one the clobbering is trying to prevent: if an irqfd is deactivated, and then its routing is changed, kvm_irq_routing_update() won't invoke kvm_arch_update_irqfd_routing() (because the irqfd isn't in the list). And so if the irqfd is in bypass mode, IRQs will continue to be
CVE-2026-23198
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-2026-23198
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": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "959a063e7f12524bc1871ad1f519787967bbcd45",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "2284bc168b148a17b5ca3b37b3d95c411f18a08d",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "6d14ba1e144e796b5fc81044f08cfba9024ca195",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "b61f9b2fcf181451d0a319889478cc53c001123e",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "ff48c9312d042bfbe826ca675e98acc6c623211c",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "4385b2f2843549bfb932e0dcf76bf4b065543a3c",
"versionType": "git"
},
{
"status": "affected",
"version": "f70c20aaf141adb715a2d750c55154073b02a9c3",
"lessThan": "b4d37cdb77a0015f51fee083598fa227cc07aaf1",
"versionType": "git"
}
],
"programFiles": [
"virt/kvm/eventfd.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.4"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.4",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.250",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.200",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.163",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.124",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.70",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.10",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"virt/kvm/eventfd.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-23198
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39780 · Revision 1
- Added to Heist Feed
- Publisher date