---
id: CVE-2026-97923
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tracing: Free histogram the var ref when its initialization fails

  create_var_ref() allocates a VAR_REF hist_field and then calls
  init_var_ref() to fill it in
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tracing: Free histogram the var ref when its initialization fails

  create_var_ref() allocates a VAR_REF hist_field and then calls
  init_var_ref() to fill it in. When tha…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-772
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    608b7751926ec08fae6a1ac4e7308195da68c362
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    4870f9071c9ea3c1423a07741b85a794db30d672
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    352f84a381e7b4651b30366e93cb858f3fa9c91a
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    4924328d6991f25b65bb7c8ff5d56c2a9b254851
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    74375caa20fe5165807b4334c783d1790b01f02a
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    222abcbe7866fef04563b6eb89fb21f627dcbc77
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    a69baeac38677270656e85753d93856a076dee57
  - >-
    Linux >= 656fe2ba85e81d00e4447bf77b8da2be3c47acb2 <
    516001d53e6b2ea95a251ee2ef54a1a689a3fd58
  - Linux 836717841a30d7845cdf9cb806ee0ff3bfa7135a
  - Linux >= 4.19.100 < 4.20
  - Linux 5.0
published: '2026-09-25'
updated: '2026-10-03'
sourceUpdated: '2026-10-03T11:18:10.060'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97923'
references:
  - url: 'https://git.kernel.org/stable/c/222abcbe7866fef04563b6eb89fb21f627dcbc77'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/352f84a381e7b4651b30366e93cb858f3fa9c91a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4870f9071c9ea3c1423a07741b85a794db30d672'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4924328d6991f25b65bb7c8ff5d56c2a9b254851'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/516001d53e6b2ea95a251ee2ef54a1a689a3fd58'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/608b7751926ec08fae6a1ac4e7308195da68c362'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/74375caa20fe5165807b4334c783d1790b01f02a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a69baeac38677270656e85753d93856a076dee57'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97923.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-97923'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541180'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-97923'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97923'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97923.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00211
epssPercentile: 0.11208
cvssSource: vendor
ingestedAt: '2026-09-25T11:06:38.888Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

tracing: Free histogram the var ref when its initialization fails

create_var_ref() allocates a VAR_REF hist_field and then calls
init_var_ref() to fill it in. When that fails the field is leaked.

commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy
var_refs") made destroy_hist_field() return early for
HIST_FIELD_FL_VAR_REF, since var refs are freed by walking the trigger's
var_refs[] array instead. create_var_ref() adds the field to that array
only after init_var_ref() has succeeded, so on this path the field is in
neither place and nothing frees it. The call was correct when it was
written, before var refs were taken out of destroy_hist_field().

init_var_ref() cannot free it either. The caller owns the field, so
init_var_ref() undoes only its own string allocations and leaves the
field alone. Freeing it there would leave create_var_ref() passing freed
memory to destroy_hist_field(), which reads its flags.

Call __destroy_hist_field(), which frees the field without consulting
the flag.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-29 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97923.json)