CVE-2026-31528 (GCVE-0-2026-31528)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-08-05 12:23
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: perf: Make sure to use pmu_ctx->pmu for groups Oliver reported that x86_pmu_del() ended up doing an out-of-bound memory access when group_sched_in() fails and needs to roll back. This *should* be handled by the transaction callbacks, but he found that when the group leader is a software event, the transaction handlers of the wrong PMU are used. Despite the move_group case in perf_event_open() and group_sched_in() using pmu_ctx->pmu. Turns out, inherit uses event->pmu to clone the events, effectively undoing the move_group case for all inherited contexts. Fix this by also making inherit use pmu_ctx->pmu, ensuring all inherited counters end up in the same pmu context. Similarly, __perf_event_read() should use equally use pmu_ctx->pmu for the group case.
References
Impacted products
Vendor Product Version
Linux Linux Version: bd27568117664b8b3e259721393df420ed51f57b
Version: bd27568117664b8b3e259721393df420ed51f57b
Version: bd27568117664b8b3e259721393df420ed51f57b
Version: bd27568117664b8b3e259721393df420ed51f57b
Version: bd27568117664b8b3e259721393df420ed51f57b
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{
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          "programFiles": [
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf: Make sure to use pmu_ctx-\u003epmu for groups\n\nOliver reported that x86_pmu_del() ended up doing an out-of-bound memory access\nwhen group_sched_in() fails and needs to roll back.\n\nThis *should* be handled by the transaction callbacks, but he found that when\nthe group leader is a software event, the transaction handlers of the wrong PMU\nare used. Despite the move_group case in perf_event_open() and group_sched_in()\nusing pmu_ctx-\u003epmu.\n\nTurns out, inherit uses event-\u003epmu to clone the events, effectively undoing the\nmove_group case for all inherited contexts. Fix this by also making inherit use\npmu_ctx-\u003epmu, ensuring all inherited counters end up in the same pmu context.\n\nSimilarly, __perf_event_read() should use equally use pmu_ctx-\u003epmu for the\ngroup case."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable perf group/inheritance paths are reached through the local perf_event_open syscall and subsequent fork/scheduling/read operations, not by network or physical input.\nAC:L - An attacker controls the perf event group composition, inherit flag, fork, and can create an over-constrained hardware group to force group_sched_in rollback; no uncontrollable race is required.\nPR:L - A normal unprivileged local user can create per-process user-space perf events under the default perf_event_paranoid=2 policy by excluding kernel profiling, so real administrative privileges are not required.\nUI:N - The attacker can trigger the sequence entirely from their own process using perf_event_open and fork/read/scheduling activity without any victim action.\nS:U - The bug corrupts kernel perf/PMU bookkeeping within the same kernel security authority and does not cross a VM, IOMMU, or other separate security boundary.\nC:H - The reported out-of-bounds access occurs in kernel PMU bookkeeping and includes memory corruption in per-CPU structures; per the higher-severity rule, this can reasonably be leveraged for kernel information disclosure.\nI:H - The rollback path can drive x86_pmu_del with inconsistent PMU transaction state, causing out-of-bounds writes such as invalid PMU array/bitmap updates, which is kernel memory corruption with potential control-flow or privilege impact.\nA:H - Even without full exploitation, the out-of-bounds kernel access can reliably produce a kernel warning/oops/panic or corrupt PMU state, causing high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:23:18.524Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/656f35b463995bee024d948440128230aacd81e1"
        },
        {
          "url": "https://git.kernel.org/stable/c/3a696e84a8b1fafdd774bb30d62919faf844d9e4"
        },
        {
          "url": "https://git.kernel.org/stable/c/35f7914e54fe7f13654c22ee045b05e4b6d8062b"
        },
        {
          "url": "https://git.kernel.org/stable/c/4c759446046500a1a6785b25725725c3ff087ace"
        },
        {
          "url": "https://git.kernel.org/stable/c/4b9ce671960627b2505b3f64742544ae9801df97"
        }
      ],
      "title": "perf: Make sure to use pmu_ctx-\u003epmu for groups",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31528",
    "datePublished": "2026-04-22T13:54:41.180Z",
    "dateReserved": "2026-03-09T15:48:24.111Z",
    "dateUpdated": "2026-08-05T12:23:18.524Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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