CVE Catalog

CVE-2026-72325

Low risk· EPSS 11%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.21%

11th percentile - higher than 11% of all known CVEs

Summary

A vulnerability was found in the Linux kernel's perf subsystem for AMD processors. During SVM (virtualization) toggling on PerfMonV2-capable CPUs, amd_pmu_enable_all() incorrectly enables Branch Sampling (BRS) even when not supported by hardware, leading to a #GP fault and potential system crash.

Risk Assessment

The risk is a possible system hang or crash during virtualization operations (e.g., disabling VMs) on AMD PerfMonV2 processors that have LBR but not BRS. This can cause service disruption and availability loss.

Recommendation

Urgently update the Linux kernel to a version containing the fix (commit resolving this issue). Monitor distribution security advisories and apply relevant patches.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: perf/x86/amd/core: Avoid enabling BRS from the SVM reload path Branch Sampling (BRS) and Last Branch Record (LBR) are mutually exclusive hardware features, and users of both are tracked via cpuc->lbr_users. When SVM is toggled on a CPU, the host perf events are reprogrammed to update the HostOnly filter bit (set when virtualization is enabled, cleared when it is disabled). On PerfMonV2-capable processors, this reprogramming is performed by calling amd_pmu_enable_all() to rewrite the event selectors. However, amd_pmu_enable_all() also calls amd_brs_enable_all(), which enables BRS whenever cpuc->lbr_users > 0. Having active LBR events satisfies this gating on processors that have LBR but not BRS. The kernel then tries to set the BRS enable bit in DebugExtnCfg (MSR 0xc000010f). Since that bit is deprecated on such hardware, the write results in a #GP: Call Trace: <IRQ> amd_pmu_enable_all+0x1d/0x90 amd_pmu_disable_virt+0x62/0xb0 kvm_arch_disable_virtualization_cpu+0xa/0x40 [kvm] hardware_disable_nolock+0x1a/0x30 [kvm] __flush_smp_call_function_queue+0x9b/0x410 __sysvec_call_function+0x18/0xc0 sysvec_call_function+0x69/0x90 </IRQ> <TASK> asm_sysvec_call_function+0x16/0x20 RIP: 0010:cpuidle_enter_state+0xc4/0x450 ? cpuidle_enter_state+0xb7/0x450 cpuidle_enter+0x29/0x40 cpuidle_idle_call+0xf5/0x160 do_idle+0x7b/0xe0 cpu_startup_entry+0x26/0x30 start_secondary+0x115/0x140 secondary_startup_64_no_verify+0x194/0x19b </TASK> Fix this by ensuring that BRS is not enabled from the event selector reprogramming path even when cpuc->lbr_users > 0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS