---
id: CVE-2026-64028
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tracing: Avoid NULL return from hist_field_name() on truncation

  hist_field_name() returns "" everywhere except the fully-qualified
  VAR_REF/EXPR case, where snprintf() …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tracing: Avoid NULL return from hist_field_name() on truncation

  hist_field_name() returns "" everywhere except the fully-qualified
  VAR_REF/EXPR case, where snprintf() …
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-476
vendor: linux
product: linux_kernel
affected:
  - linux_kernel = 6.6.141
  - linux_kernel = 6.12.91
  - linux_kernel = 6.18.33
  - linux_kernel = 7.0.10
  - linux_kernel = 7.1
published: '2026-07-19'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T15:23:52.833'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64028'
references:
  - url: 'https://git.kernel.org/stable/c/0402a1d3ddec565132867337ed44514a09d84728'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/37377b39ff86dacbc533275c1155210d4fd5dc91'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/576ec047d20b368b43c4d5db98c4f2e0f3c101ec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/915c1254fe0788abddc31095b360e9dc98907a34'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/be4e99038c1603fa6b329d8ee3e364825e17c353'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d6c8b3ebdcdb12b59ad4212acb137cc56cae453d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e3f5d42cdc2f167719564693675f1eead81378ea'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e91687643c440ca3997d67646e6f80b92edc6703'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00231
epssPercentile: 0.12844
ingestedAt: '2026-10-13T15:33:40.026Z'
---

## Overview

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

tracing: Avoid NULL return from hist_field_name() on truncation

hist_field_name() returns "" everywhere except the fully-qualified
VAR_REF/EXPR case, where snprintf() truncation returns NULL early
and bypasses the bottom NULL->"" guard. Callers don't expect NULL:
strcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758
and the strcmp() in the sort-key match loop at :4804 both deref it.

system and event_name are bounded by MAX_EVENT_NAME_LEN, but the
field name on a VAR_REF is kstrdup'd from a histogram variable
name parsed out of the trigger string and has no length cap, so
a long enough var name in a fully qualified reference can reach
the truncation path.

Keep the length check but leave field_name as "" on overflow.

## Affected

- `linux_kernel = 6.6.141`
- `linux_kernel = 6.12.91`
- `linux_kernel = 6.18.33`
- `linux_kernel = 7.0.10`
- `linux_kernel = 7.1`

## Remediation

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