CVE-2026-23380 (GCVE-0-2026-23380)
Vulnerability from cvelistv5
Published
2026-03-25 10:27
Modified
2026-05-11 22:05
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON. Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork. Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.
References
Impacted products
Vendor Product Version
Linux Linux Version: cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64
Version: cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64
Version: cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64
Version: cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/ring_buffer.h",
            "kernel/trace/ring_buffer.c",
            "kernel/trace/trace.c"
          ],
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          "versions": [
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          "vendor": "Linux",
          "versions": [
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              "version": "6.10"
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              "version": "0",
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              "status": "unaffected",
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              "status": "unaffected",
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              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.17",
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix WARN_ON in tracing_buffers_mmap_close\n\nWhen a process forks, the child process copies the parent\u0027s VMAs but the\nuser_mapped reference count is not incremented. As a result, when both the\nparent and child processes exit, tracing_buffers_mmap_close() is called\ntwice. On the second call, user_mapped is already 0, causing the function to\nreturn -ENODEV and triggering a WARN_ON.\n\nNormally, this isn\u0027t an issue as the memory is mapped with VM_DONTCOPY set.\nBut this is only a hint, and the application can call\nmadvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the\napplication does that, it can trigger this issue on fork.\n\nFix it by incrementing the user_mapped reference count without re-mapping\nthe pages in the VMA\u0027s open callback."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:05:45.422Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/91f3e8d84c89918769e71393f839c9fefadc2580"
        },
        {
          "url": "https://git.kernel.org/stable/c/cdd96641b64297a2db42676f051362b76280a58b"
        },
        {
          "url": "https://git.kernel.org/stable/c/b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0"
        },
        {
          "url": "https://git.kernel.org/stable/c/e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e"
        }
      ],
      "title": "tracing: Fix WARN_ON in tracing_buffers_mmap_close",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23380",
    "datePublished": "2026-03-25T10:27:59.682Z",
    "dateReserved": "2026-01-13T15:37:46.007Z",
    "dateUpdated": "2026-05-11T22:05:45.422Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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