CVE-2024-26992KVM: x86/pmu: Disable support for adaptive PEBS

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/pmu: Disable support for adaptive PEBS Drop support for virtualizing adaptive PEBS, as KVM's implementation is architecturally broken without an obvious/easy path forward, and because exposing adaptive PEBS can leak host LBRs to the guest, i.e. can leak host kernel addresses to the guest. Bug #1 is that KVM doesn't account for the upper 32 bits of IA32_FIXED_CTR_CTRL when (re)programming fixed counters, e.g fixed_ctrl_field() drops the upper bits, reprogram_fixed_counters() stores local variables as u8s and truncates the upper bits too, etc. Bug #2 is that, because KVM _always_ sets precise_ip to a non-zero value for PEBS events, perf will _always_ generate an adaptive record, even if the guest requested a basic record. Note, KVM will also enable adaptive PEBS in individual *counter*, even if adaptive PEBS isn't exposed to the guest, but this is benign as MSR_PEBS_DATA_CFG is guaranteed to be zero, i.e. the guest will only ever see Basic records. Bug #3 is in perf. intel_pmu_disable_fixed() doesn't clear the upper bits either, i.e. leaves ICL_FIXED_0_ADAPTIVE set, and intel_pmu_enable_fixed() effectively doesn't clear ICL_FIXED_0_ADAPTIVE either. I.e. perf _always_ enables ADAPTIVE counters, regardless of what KVM requests. Bug #4 is that adaptive PEBS *might* effectively bypass event filters set by the host, as "Updated Memory Access Info Group" records information that might be disallowed by userspace via KVM_SET_PMU_EVENT_FILTER. Bug #5 is that KVM doesn't ensure LBR MSRs hold guest values (or at least zeros) when entering a vCPU with adaptive PEBS, which allows the guest to read host LBRs, i.e. host RIPs/addresses, by enabling "LBR Entries" records. Disable adaptive PEBS support as an immediate fix due to the severity of the LBR leak in particular, and because fixing all of the bugs will be non-trivial, e.g. not suitable for backporting to stable kernels. Note! This will break live migration, but trying to make KVM play nice with live migration would be quite complicated, wouldn't be guaranteed to work (i.e. KVM might still kill/confuse the guest), and it's not clear that there are any publicly available VMMs that support adaptive PEBS, let alone live migrate VMs that support adaptive PEBS, e.g. QEMU doesn't support PEBS in any capacity.

Timeline

Scores

EPSS (exploitation in 30 days)

0.23% · top 86% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.3.

Affected products

• Linux · Linux

  • affected c59a1f106f5cd4843c097069ff1bb2ad72103a67 – < 0fb74c00d140a66128afc0003785dcc57e69d312
  • affected c59a1f106f5cd4843c097069ff1bb2ad72103a67 – < 037e48ceccf163899374b601afb6ae8d0bf1d2ac
  • affected c59a1f106f5cd4843c097069ff1bb2ad72103a67 – < 7a7650b3ac23e5fc8c990f00e94f787dc84e3175
  • affected c59a1f106f5cd4843c097069ff1bb2ad72103a67 – < 9e985cbf2942a1bb8fcef9adc2a17d90fd7ca8ee

• Linux · Linux

  • affected 6.0
  • unaffected < 6.0
  • unaffected 6.1.88 – ≤ 6.1.*
  • unaffected 6.6.29 – ≤ 6.6.*
  • unaffected 6.8.8 – ≤ 6.8.*
  • unaffected 6.9 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2024-24254 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-26992](https://cveledger.app/badge/CVE-2024-26992.svg)](https://cveledger.app/cve/CVE-2024-26992)

Record last updated 5 Aug 2026, 11:28 UTC.