tracing: Fix memory corruption from the histogram stacktrace modifier

{
  "id": "24f9779a4ea26531b307c2954face1c3fb71a084ff221bf2aec7adecd03337e2",
  "url": "https://osv.dev/vulnerability/CVE-2026-97936",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tracing: Fix memory corruption from the histogram stacktrace modifier",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tracing: Fix memory corruption from the histogram stacktrace modifier parse_field() sets HIST_FIELD_FL_STACKTRACE from the \".stacktrace\" modifier before it looks the field name up, and nothing afterwards checks that the name resolved to a field which holds a stacktrace. create_hist_field() picks HIST_FIELD_FN_STACK on the strength of the field pointer alone, which reads a __data_loc word from the record and follows its low 16 bits as an offset into the same record. event_hist_trigger() takes the first word there as an entry count and copies that many longs into a 31 entry array: n_entries = *stack; memcpy(entries, ++stack, n_entries * sizeof(unsigned long)); Neither end of that copy is bounded, and the count is whatever the event holds at the offset, so any field will do: # cd /sys/kernel/tracing/events/sched/sched_process_fork # echo 'hist:keys=parent_pid.stacktrace' > trigger # (true) BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:rb_insert_color+0x18/0x130 timerqueue_linked_add+0x7e/0xd0 enqueue_hrtimer+0x39/0xb0 __hrtimer_run_queues+0x10f/0x1f0 RIP: 0010:memcpy+0xc/0x30 event_hist_trigger+0x165/0x690 The timer interrupt landed on the rbtree the copy had already run over. No debug options are needed for this; KASAN reports the same write as an out-of-bounds read of 13835058055416381440 bytes. Documentation/trace/histogram.rst already states the rule, \"must be a long[] type\", so e",
    "evidence": "osv:CVE-2026-97936",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.158",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.111",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.53",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-97936",
      "aliases": [
        "CVE-2026-97936"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "cc5fc8bfc961eeb99b7e8dffbeff7a3f6995d314"
                },
                {
                  "fixed": "98da3379cdee343f671dac89b9afbd8b071f2591"
                },
                {
                  "fixed": "e183b84968d4a6ea476d806ea97668405aa56880"
                },
                {
                  "fixed": "57bfc2a17954d173d2a4182f3b582ffbb23aff64"
                },
                {
                  "fixed": "55caaf25da2c2bb9b75307e4c868726cb954b1d6"
                },
                {
                  "fixed": "a5e70ba87ca8ebc79b4e63de302d03b0625fe153"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97936.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.3.0"
                },
                {
                  "fixed": "6.6.158"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.12.111"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.53"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97936.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.193192431Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/55caaf25da2c2bb9b75307e4c868726cb954b1d6",
        "https://git.kernel.org/stable/c/57bfc2a17954d173d2a4182f3b582ffbb23aff64",
        "https://git.kernel.org/stable/c/98da3379cdee343f671dac89b9afbd8b071f2591",
        "https://git.kernel.org/stable/c/a5e70ba87ca8ebc79b4e63de302d03b0625fe153",
        "https://git.kernel.org/stable/c/e183b84968d4a6ea476d806ea97668405aa56880",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97936.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-97936",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97936.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-97936",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 504494,
  "published_at": "2026-09-25T10:22:50.446+00:00"
}