CVE-2026-31558 (GCVE-0-2026-31558)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:35 – Updated: 2026-08-05 12:23
VLAI
Title
LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust
Summary
In the Linux kernel, the following vulnerability has been resolved: LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust kvm_get_vcpu_by_cpuid() takes a cpuid parameter whose type is int, so cpuid can be negative. Let kvm_get_vcpu_by_cpuid() return NULL for this case so as to make it more robust. This fix an out-of-bounds access to kvm_arch::phyid_map::phys_map[].
Severity
8.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 73516e9da512adc63ba3859fbd82a21f6257348f , < 596c3f8069c4792f22fce8c4452f44410032d910 (git)
Affected: 73516e9da512adc63ba3859fbd82a21f6257348f , < 878cf6acb4fd8ab4126cf9d369a5bb0e23123418 (git)
Affected: 73516e9da512adc63ba3859fbd82a21f6257348f , < 47857b05bd50db01e211a1b6f513d57901cd3e6b (git)
Affected: 73516e9da512adc63ba3859fbd82a21f6257348f , < 2db06c15d8c7a0ccb6108524e16cd9163753f354 (git)
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Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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{
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          "programFiles": [
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              "value": "AV:L - Exploitation requires local ability to run/control a LoongArch KVM guest or access KVM ioctls through `/dev/kvm`; the vulnerable code is not reachable directly over a network.\nAC:L - The attacker can directly supply the negative CPUID condition through guest hypercall register state or KVM interrupt-controller state, and no race or external timing condition is required.\nPR:L - The attacker needs access to a KVM VM or `/dev/kvm`, but the path does not require real host root or an init-namespace capability once KVM access is available.\nUI:N - No victim user action is required after the attacker can run the guest/KVM operation; the trigger is a direct hypercall or ioctl-driven interrupt-controller operation.\nS:C - The vulnerable component is host KVM, and a malicious guest or KVM user can affect host kernel memory, crossing the VM isolation boundary.\nC:H - The bug is an out-of-bounds access to the host kernel `phys_map` array, and under the required higher-severity rule this is treated as potentially exposing host kernel memory during exploitation.\nI:H - If the out-of-bounds entry is interpreted as an enabled vCPU, later interrupt-injection paths dereference and modify state through a bogus `struct kvm_vcpu` pointer, making host kernel memory corruption defensible.\nA:H - The reported failure includes UBSAN out-of-bounds warnings in host KVM, and attacker-controlled negative indices can reasonably cause host kernel oops, panic, or repeated denial of service."
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    "dateReserved": "2026-03-09T15:48:24.116Z",
    "dateUpdated": "2026-08-05T12:23:30.748Z",
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-28T11:52:37+00:00",
      "cve": "CVE-2026-31558",
      "id": "CVE-2026-31558",
      "initial_release_date": "2026-04-24T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31558.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-06T01:24:31Z",
      "cve": "CVE-2026-31558",
      "id": "CVE-2026-31558",
      "initial_release_date": "2026-04-25T01:39:29Z",
      "product_status:known_not_affected": "315",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-31558",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-31558.json",
      "version": "5"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.