CVE-2026-89513 (GCVE-0-2026-89513)
Vulnerability from cvelistv5
Published
2026-09-11 19:43
Modified
2026-10-19 08:48
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: RISC-V: KVM: Fix PMU event info array size overflow SBI PMU EVENT_GET_INFO stores guest-controlled num_events * sizeof(*einfo) in a 32-bit integer. On RV64, num_events = 0x10000001 makes 0x100000010 truncate to 16. KVM then allocates one entry but loops over the original num_events, causing out-of-bounds reads and writes. A nested guest triggered: BUG: KASAN: slab-out-of-bounds in kvm_riscv_vcpu_pmu_event_info+0xa4/0x142 Read of size 4 at addr ff600000074d46b0 by task init/1 Call Trace: [<ffffffff8006471c>] kvm_riscv_vcpu_pmu_event_info+0xa4/0x142 [<ffffffff800690c0>] kvm_sbi_ext_pmu_handler+0xca/0x268 [<ffffffff8006779e>] kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6 [<ffffffff8006008c>] kvm_riscv_vcpu_exit+0x48c/0x540 [<ffffffff8005ea0a>] kvm_arch_vcpu_ioctl_run+0x37e/0xc80 Allocated by task 1: __kmalloc_noprof+0x19e/0x4b0 kvm_riscv_vcpu_pmu_event_info+0x72/0x142 kvm_sbi_ext_pmu_handler+0xca/0x268 kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6 kvm_riscv_vcpu_exit+0x48c/0x540 kvm_arch_vcpu_ioctl_run+0x37e/0xc80 The buggy address is located 0 bytes to the right of allocated 16-byte region [ff600000074d46a0, ff600000074d46b0) Store the shared-memory size in size_t and reject multiplication overflow. Allocate the guest-driven array with GFP_KERNEL_ACCOUNT so it is charged to kmemcg, and use __GFP_NOWARN to suppress allocation failure warnings. Use kvcalloc() to allow vmalloc fallback and an unsigned long loop index to match num_events.
References
Impacted products
Vendor Product Version
Linux Linux Version: e309fd113b9f6c34672a487be08fecb7e12e7e29
Version: e309fd113b9f6c34672a487be08fecb7e12e7e29
Version: e309fd113b9f6c34672a487be08fecb7e12e7e29
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/kvm/vcpu_pmu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ddbd71a3780942918a7d116d666313e5b3304d73",
              "status": "affected",
              "version": "e309fd113b9f6c34672a487be08fecb7e12e7e29",
              "versionType": "git"
            },
            {
              "lessThan": "82088f88c96b99c27a974d09b02c2b133262fadf",
              "status": "affected",
              "version": "e309fd113b9f6c34672a487be08fecb7e12e7e29",
              "versionType": "git"
            },
            {
              "lessThan": "735bc20c24187ca419c9d5e63860a54b91be34bd",
              "status": "affected",
              "version": "e309fd113b9f6c34672a487be08fecb7e12e7e29",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/riscv/kvm/vcpu_pmu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRISC-V: KVM: Fix PMU event info array size overflow\n\nSBI PMU EVENT_GET_INFO stores guest-controlled num_events * sizeof(*einfo)\nin a 32-bit integer. On RV64, num_events = 0x10000001 makes 0x100000010\ntruncate to 16. KVM then allocates one entry but loops over the original\nnum_events, causing out-of-bounds reads and writes. A nested guest\ntriggered:\n\nBUG: KASAN: slab-out-of-bounds in kvm_riscv_vcpu_pmu_event_info+0xa4/0x142\nRead of size 4 at addr ff600000074d46b0 by task init/1\nCall Trace:\n[\u003cffffffff8006471c\u003e] kvm_riscv_vcpu_pmu_event_info+0xa4/0x142\n[\u003cffffffff800690c0\u003e] kvm_sbi_ext_pmu_handler+0xca/0x268\n[\u003cffffffff8006779e\u003e] kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6\n[\u003cffffffff8006008c\u003e] kvm_riscv_vcpu_exit+0x48c/0x540\n[\u003cffffffff8005ea0a\u003e] kvm_arch_vcpu_ioctl_run+0x37e/0xc80\nAllocated by task 1:\n __kmalloc_noprof+0x19e/0x4b0\n kvm_riscv_vcpu_pmu_event_info+0x72/0x142\n kvm_sbi_ext_pmu_handler+0xca/0x268\n kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6\n kvm_riscv_vcpu_exit+0x48c/0x540\n kvm_arch_vcpu_ioctl_run+0x37e/0xc80\nThe buggy address is located 0 bytes to the right of\n allocated 16-byte region [ff600000074d46a0, ff600000074d46b0)\n\nStore the shared-memory size in size_t and reject multiplication overflow.\nAllocate the guest-driven array with GFP_KERNEL_ACCOUNT so it is charged\nto kmemcg, and use __GFP_NOWARN to suppress allocation failure warnings.\nUse kvcalloc() to allow vmalloc fallback and an unsigned long loop index\nto match num_events."
        }
      ],
      "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 - The overflow is reached when a RISC-V KVM guest issues an SBI ECALL (EXC_SUPERVISOR_SYSCALL) for SBI_EXT_PMU_EVENT_GET_INFO, handled on the host KVM_RUN path via kvm_riscv_vcpu_exit, kvm_riscv_vcpu_sbi_ecall, kvm_sbi_ext_pmu_handler, and kvm_riscv_vcpu_pmu_event_info; this is a local guest hypercall path with no network or physical exposure.\nAC:L - A guest that sets flags=0, a 16-byte-aligned shared-memory GPA, and num_events=0x10000001 on RV64 makes num_events*sizeof(*einfo) truncate from 0x100000010 to 16, so kzalloc gets one entry while the loop uses the original count; the attacker controls every parameter and needs no race or uncontrollable host layout.\nPR:L - Issuing the SBI ECALL requires VS-mode in a KVM guest (tenant kernel or custom image) or a host kvm-group user running QEMU, not host init-namespace root; kvm_sbi_ext_pmu_handler has no capability check, and SBI PMU is enabled by default once kvm_riscv_vcpu_pmu_init succeeds.\nUI:N - The attacker guest issues SBI_EXT_PMU_EVENT_GET_INFO itself during KVM_RUN; no separate victim action such as attaching a device, mounting a filesystem, or confirming a prompt is required.\nS:C - The slab out-of-bounds access runs in the host kernel while handling a guest SBI call, crossing the KVM guest-to-hypervisor boundary so host heap corruption can compromise the hypervisor and co-located VMs, which CNA guidance rates Changed for KVM guest-to-host escape.\nC:H - After the truncated 16-byte allocation, the loop reads event_idx and event_data from adjacent host slab for 0x10000001 entries; that unbounded host-heap out-of-bounds read, together with the following heap corruption, can be leveraged for kernel memory disclosure.\nI:H - The same loop writes einfo[i].output (0 or 1) past the 16-byte object at a 16-byte stride for about 2^28 iterations, an unbounded host-slab out-of-bounds write that smashes neighboring objects and heap metadata and is scored High per CNA out-of-bounds-write guidance.\nA:H - KASAN reported a host slab-out-of-bounds in kvm_riscv_vcpu_pmu_event_info, and walking billions of bytes past a 16-byte allocation reliably oopses or panics the host kernel, denying service to the hypervisor and every co-located VM."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:48:04.610Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ddbd71a3780942918a7d116d666313e5b3304d73"
        },
        {
          "url": "https://git.kernel.org/stable/c/82088f88c96b99c27a974d09b02c2b133262fadf"
        },
        {
          "url": "https://git.kernel.org/stable/c/735bc20c24187ca419c9d5e63860a54b91be34bd"
        }
      ],
      "title": "RISC-V: KVM: Fix PMU event info array size overflow",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89513",
    "datePublished": "2026-09-11T19:43:57.960Z",
    "dateReserved": "2026-09-11T19:38:34.717Z",
    "dateUpdated": "2026-10-19T08:48:04.610Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




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.