CVE-2026-89907 (GCVE-0-2026-89907)
Vulnerability from cvelistv5
Published
2026-09-16 10:32
Modified
2026-10-19 08:54
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: KVM: Validate MSI data before routing it to EIOINTC
pch_msi_set_irq() passes e->msi.data straight into eiointc_set_irq() as
the irq number. The MSI data comes from userspace, that either via a
KVM_IRQ_ROUTING_MSI entry set with KVM_SET_GSI_ROUTING (used by irqfd
and KVM_IRQ_LINE) or directly via KVM_SIGNAL_MSI, and is never checked
against EIOINTC_IRQS.
eiointc_set_irq() uses the value with __set_bit()/__clear_bit() on the
256-bit isr bitmap, eiointc_update_irq() then indexes sw_coremap[] and
the per-cpu coreisr/sw_coreisr bitmaps with it. Therefore a data value
>= 256 reads and writes memory past the end of those arrays, i.e. any
process holding a VM fd can corrupt kernel memory beyond the allocation
of loongarch_eiointc.
Reject MSI data that doesn't fit in the EIOINTC irq space. The DMSINTC
path is unaffected as it decodes the vector from the address and masks
it.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/loongarch/kvm/intc/pch_pic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "506f03b5f869cbae50d31b50d80d4a5735d47f94",
"status": "affected",
"version": "1928254c5ccb7bdffd7f0334e1ce250e9ce4de94",
"versionType": "git"
},
{
"lessThan": "83715a40a2d30d23719e0b25380ba82ff905195b",
"status": "affected",
"version": "1928254c5ccb7bdffd7f0334e1ce250e9ce4de94",
"versionType": "git"
},
{
"lessThan": "501514d6ebd2111c353a1296f25dbe22fbd64657",
"status": "affected",
"version": "1928254c5ccb7bdffd7f0334e1ce250e9ce4de94",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/loongarch/kvm/intc/pch_pic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"lessThan": "6.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.57",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.5",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "6.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: KVM: Validate MSI data before routing it to EIOINTC\n\npch_msi_set_irq() passes e-\u003emsi.data straight into eiointc_set_irq() as\nthe irq number. The MSI data comes from userspace, that either via a\nKVM_IRQ_ROUTING_MSI entry set with KVM_SET_GSI_ROUTING (used by irqfd\nand KVM_IRQ_LINE) or directly via KVM_SIGNAL_MSI, and is never checked\nagainst EIOINTC_IRQS.\n\neiointc_set_irq() uses the value with __set_bit()/__clear_bit() on the\n256-bit isr bitmap, eiointc_update_irq() then indexes sw_coremap[] and\nthe per-cpu coreisr/sw_coreisr bitmaps with it. Therefore a data value\n\u003e= 256 reads and writes memory past the end of those arrays, i.e. any\nprocess holding a VM fd can corrupt kernel memory beyond the allocation\nof loongarch_eiointc.\n\nReject MSI data that doesn\u0027t fit in the EIOINTC irq space. The DMSINTC\npath is unaffected as it decodes the vector from the address and masks\nit."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - pch_msi_set_irq() is reached only via local KVM VM-fd ioctls on /dev/kvm: KVM_SIGNAL_MSI, or KVM_SET_GSI_ROUTING with a KVM_IRQ_ROUTING_MSI entry then irqfd/KVM_IRQ_LINE. No network, Bluetooth, or physical path supplies the unbounded MSI data.\nAC:L - A single KVM_SIGNAL_MSI (or irqfd injection after installing a KVM_IRQ_ROUTING_MSI entry) with attacker-chosen msi.data \u003e= 256 deterministically drives __set_bit()/__clear_bit() on isr and indexes sw_coremap[] past EIOINTC_IRQS; the attacker fully controls the irq index with no race or uncontrollable layout.\nPR:L - Exploitation requires only opening /dev/kvm and holding a VM fd (kvm-group membership on typical LoongArch hosts, or equivalent unprivileged VM access), then creating the in-kernel EIOINTC/PCH-PIC/IPI devices. Init-namespace root is not required.\nUI:N - No victim interaction is required. The attacker creates the in-kernel LoongArch irqchip devices on a VM they control and issues KVM_SIGNAL_MSI or irqfd themselves; no mount, file open, or other user action is needed.\nS:C - A KVM VM operator corrupts host kernel memory beyond the loongarch_eiointc allocation from the KVM userspace interface, crossing the VM-to-host virtualization boundary rather than confining impact to the attacker\u0027s VM security scope.\nC:H - Unbounded msi.data causes out-of-bounds __set_bit()/__clear_bit() on the 256-bit isr bitmap and an out-of-bounds sw_coremap[irq] read past the loongarch_eiointc object. Per kernel guidance such OOB memory corruption is High confidentiality impact.\nI:H - The attacker fully controls the bit index via 32-bit MSI data, yielding arbitrary-offset bit set/clear from s-\u003eisr and further OOB writes into coreisr/sw_coreisr when a valid vCPU id is observed. That out-of-bounds write is usable for host privilege escalation.\nA:H - Indexing the EIOINTC bitmaps and sw_coremap[] with irq \u003e= 256 can immediately oops or panic the host kernel, and corrupting adjacent slab objects breaks later irq injection, denying service to the host and co-resident VMs."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T08:54:39.939Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/506f03b5f869cbae50d31b50d80d4a5735d47f94"
},
{
"url": "https://git.kernel.org/stable/c/83715a40a2d30d23719e0b25380ba82ff905195b"
},
{
"url": "https://git.kernel.org/stable/c/501514d6ebd2111c353a1296f25dbe22fbd64657"
}
],
"title": "LoongArch: KVM: Validate MSI data before routing it to EIOINTC",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-89907",
"datePublished": "2026-09-16T10:32:05.925Z",
"dateReserved": "2026-09-11T19:38:34.774Z",
"dateUpdated": "2026-10-19T08:54:39.939Z",
"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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