# CVE-2026-72325: perf/x86/amd/core: Avoid enabling BRS from the SVM reload path

> A local attacker can trigger a kernel crash by toggling SVM on AMD processors with active LBR events, causing a general protection fault.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-96558, BELL-CVE-2026-72325, DEBIAN-CVE-2026-72325, GHSA-522h-ffm3-c569, UBUNTU-CVE-2026-72325

## What is CVE-2026-72325?

CVE-2026-72325 is a denial of service vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

## Which versions are affected by CVE-2026-72325?


## How do I fix CVE-2026-72325?

Apply the vendor's patch.

## Is CVE-2026-72325 being exploited?

There is no known exploitation of CVE-2026-72325 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72325 and fix it if it is affected.

What it is: CVE-2026-72325 is a denial of service vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72325 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-72325/ (Markdown: https://insights.sbomify.com/CVE-2026-72325/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72325
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72325
- OSV: https://osv.dev/vulnerability/CVE-2026-72325

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72325/
Summaries are generated and may contain mistakes; the official description above is the record.