CVE-2026-89513: Linux kernel · RISC-V: KVM: Fix PMU event info array size overflow SBI PMU EVENT_GET_INFO stores
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 28 Oct 2026, 01:01 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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
- ubuntu.com/security/CVE-2026-89513 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89513 (opens in a new tab)
- git.kernel.org/linus/735bc20c24187ca419c9d5e63860a54b91be34bd (opens in a new tab)
- git.kernel.org/stable/c/735bc20c24187ca419c9d5e63860a54b91be34bd (opens in a new tab)
- git.kernel.org/stable/c/82088f88c96b99c27a974d09b02c2b133262fadf (opens in a new tab)