{"id":"CVE-2026-89907","state":"PUBLISHED","title":"LoongArch: KVM: Validate MSI data before routing it to EIOINTC","description":"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->msi.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>= 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't fit in the EIOINTC irq space. The DMSINTC\npath is unaffected as it decodes the vector from the address and masks\nit.","publishedAt":"2026-09-16T10:32:05.925Z","updatedAt":"2026-10-19T08:54:39.939Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"506f03b5f869cbae50d31b50d80d4a5735d47f94","versionType":"git"},{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"83715a40a2d30d23719e0b25380ba82ff905195b","versionType":"git"},{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"501514d6ebd2111c353a1296f25dbe22fbd64657","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/loongarch/kvm/intc/pch_pic.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/loongarch/kvm/intc/pch_pic.c"]}],"references":["https://git.kernel.org/stable/c/506f03b5f869cbae50d31b50d80d4a5735d47f94","https://git.kernel.org/stable/c/83715a40a2d30d23719e0b25380ba82ff905195b","https://git.kernel.org/stable/c/501514d6ebd2111c353a1296f25dbe22fbd64657"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89907.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89907","state":"PUBLISHED","datePublished":"2026-09-16T10:32:05.925Z","dateUpdated":"2026-10-19T08:54:39.939Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.774Z"},"containers":{"cna":{"title":"LoongArch: KVM: Validate MSI data before routing it to EIOINTC","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->msi.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>= 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't fit in the EIOINTC irq space. The DMSINTC\npath is unaffected as it decodes the vector from the address and masks\nit."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"506f03b5f869cbae50d31b50d80d4a5735d47f94","versionType":"git"},{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"83715a40a2d30d23719e0b25380ba82ff905195b","versionType":"git"},{"version":"1928254c5ccb7bdffd7f0334e1ce250e9ce4de94","status":"affected","lessThan":"501514d6ebd2111c353a1296f25dbe22fbd64657","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/loongarch/kvm/intc/pch_pic.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/loongarch/kvm/intc/pch_pic.c"]}],"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"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 >= 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's 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->isr 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 >= 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":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:54:39.939Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}