High severity · published Sep 11, 2026
CVE-2026-89513
RISC-V: KVM: Fix PMU event info array size overflow
8.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
e309fd113b9f6c34672a487be08fecb7e12e7e29 before ddbd71a3780942918a7d116d666313e5b3304d73; e309fd113b9f6c34672a487be08fecb7e12e7e29 before 82088f88c96b99c27a974d09b02c2b133262fadf; e309fd113b9f6c34672a487be08fecb7e12e7e29 before 735bc20c24187ca419c9d5e63860a54b91be34bd; 6.18 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89513
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-89513
git.kernel.org
https://git.kernel.org/stable/c/735bc20c24187ca419c9d5e63860a54b91be34bd
git.kernel.org
https://git.kernel.org/stable/c/82088f88c96b99c27a974d09b02c2b133262fadf
git.kernel.org
https://git.kernel.org/stable/c/ddbd71a3780942918a7d116d666313e5b3304d73
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