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tracing: Free histogram the field rejected for a bad modifier

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: tracing: Free histogram the field rejected for a bad modifier Writing a hist trigger whose value or variable carries a modifier that is not allowed there leaks the fields that were built for it. __create_val_field() takes the field from parse_expr() and stores it in hist_data->fields[] only after the modifier checks have run: hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs); ... if (hist_field->flags & HIST_FIELD_FL_VAR) { if (hist_field->flags & (...)) goto err; } else { if (hist_field->flags & (...)) goto err; } hist_data->fields[val_idx] = hist_field; Both checks jump past that store, and the err label returns without freeing anything. The error unwinds to create_hist_data(), which calls destroy_hist_data() -> destroy_hist_fields(), and that reaches a field only by walking fields[]. A field that never got there is unreachable. commit e0213434fe3e ("tracing: Do not let histogram values have some modifiers") set ret to -EINVAL and fell through to the store, which left the field owned by fields[] and freed along with the rest of hist_data. Splitting the check into a value case and a variable case replaced that fall-through with a goto that skips it. With CONFIG_DEBUG_KMEMLEAK, 200 writes of # echo 'hist:keys=prev_pid:vals=next_pid.log2' > \ events/sched/sched_switch/trigger each correctly rejected with -EINVAL, leave 332 unreferenced objects (63744 bytes) reported at create_hi

Announced Source revision 1
Original source ↗

CVE-2026-97921

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-97921

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "7403630eb94c1d664fb873f967427ef2f6ee3699",
        "lessThan": "a2652fcf96b63e9da04951e4e58e6a0672df695d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c",
        "lessThan": "3d42fed18b2c5707b6332ebe87b789fd768eb01b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c",
        "lessThan": "e787361bb6b0026ea3eb4d3fa7a304c7fcb99555",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c",
        "lessThan": "b22dc0add7d72b8bd9cae3188db0dd65da1c8652",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c",
        "lessThan": "891c21f6d5673b2a519b536243bfc6dd2d35beb6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c",
        "lessThan": "230234d12ce42ab04132a32c3a848f07a5d27a71",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8d505d06d7330f5d67d3e5e9e1c647fb0b10ddad",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.1.33",
        "lessThan": "6.1.189",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.3.7",
        "lessThan": "6.4",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "kernel/trace/trace_events_hist.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.4"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.4",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.111",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.53",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/trace/trace_events_hist.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-97921

Source reference: /cveMetadata/cveId

Publisher severity

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Event
#38071 · Revision 1
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