{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kernel/perf_cpum_sf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4b3bdfa89635db6a53e02955548bd07bebcae233",
              "status": "affected",
              "version": "8a6fe8f21ec4f049a7b1fe120ad50a5065a9c7a8",
              "versionType": "git"
            },
            {
              "lessThan": "f55bd479d8663a4a4e403b3d308d3d1aa33d92df",
              "status": "affected",
              "version": "8a6fe8f21ec4f049a7b1fe120ad50a5065a9c7a8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/kernel/perf_cpum_sf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.2",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/cpum_sf: Fix and protect memory allocation of SDBs with mutex\n\nReservation of the PMU hardware is done at first event creation\nand is protected by a pair of mutex_lock() and mutex_unlock().\nAfter reservation of the PMU hardware the memory\nrequired for the PMUs the event is to be installed on is\nallocated by allocate_buffers() and alloc_sampling_buffer().\nThis done outside of the mutex protection.\nWithout mutex protection two or more concurrent invocations of\nperf_event_init() may run in parallel.\nThis can lead to allocation of Sample Data Blocks (SDBs)\nmultiple times for the same PMU.\nPrevent this and protect memory allocation of SDBs by\nmutex."
        }
      ],
      "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 code is reached only through the local `perf_event_open(2)` syscall on s390, via `cpumsf_pmu_event_init()` \u2192 `__hw_perf_event_init()`. There is no remote or adjacent-network path to the CPU-measurement sampling facility.\nAC:L - The attacker controls both sides of the race by simply calling `perf_event_open()` from two or more of its own threads in a loop; `perf_try_init_event()` holds no global lock, and the race window spans a long `GFP_KERNEL` page-allocation loop (hundreds to thousands of pages, freely sleeping), making it trivially winnable.\nPR:L - Under the upstream default `perf_event_paranoid = 2`, an ordinary unprivileged user may open a per-task sampling event (`pid=self`, `cpu=-1`, `exclude_kernel=1`) with no capability at all, and that `cpu == -1` branch is precisely the one that allocates buffers on every online CPU. A local account is required, so not PR:N.\nUI:N - The attacking process triggers the race entirely on its own by issuing concurrent syscalls; no action by any other user or victim process is needed.\nS:U - The corruption is confined to kernel memory managed by the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The racing `free_sampling_buffer()` treats still-zero SDBT entries as SDB pointers and walks past the end of the table page, reading unbounded adjacent kernel memory as physical addresses; combined with the resulting use-after-free, the hardware keeps writing sample data into freed/reallocated pages that the attacker reads back through the perf ring buffer.\nI:H - The race yields double-free, use-after-free writes into freed SDBT/SDB pages, and `free_page()` on in-use pages (including physical page 0 via `phys_to_virt(0)`), all classic page-allocator grooming primitives that can be escalated to arbitrary write and control-flow hijack.\nA:H - At minimum each won race orphans an entire SDBT/SDB chain (up to ~32 MB per online CPU) and can be repeated in a loop to exhaust memory; the double-free and freeing of live kernel pages readily produce a page-allocator BUG or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:46:11.395Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4b3bdfa89635db6a53e02955548bd07bebcae233"
        },
        {
          "url": "https://git.kernel.org/stable/c/f55bd479d8663a4a4e403b3d308d3d1aa33d92df"
        }
      ],
      "title": "s390/cpum_sf: Fix and protect memory allocation of SDBs with mutex",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2024-56706",
    "datePublished": "2024-12-28T09:46:27.297Z",
    "dateReserved": "2024-12-27T15:00:39.856Z",
    "dateUpdated": "2026-08-05T11:46:11.395Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}