---
id: CVE-2026-74314
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Cancel special fields on map value recycle

  Map update and delete paths currently call bpf_obj_free_fields() when a
  value is being replaced or recycled
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Cancel special fields on map value recycle

  Map update and delete paths currently call bpf_obj_free_fields() when a
  value is being replaced or recycled. That makes…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-763
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:17:38.840'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74314'
references:
  - url: 'https://git.kernel.org/stable/c/9ea734e2cc0143d7429ab7dc0b20c85e5836183c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a3a81d247651218e47153f2d2afd7aee236726fd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74314.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-74314'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2516759'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-74314'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74314'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081552-CVE-2026-74314-fc58@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00177
epssPercentile: 0.07189
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:53:09.033904Z'
scores:
  nvd: 7.8
  vendor: 5.5
  cna: 7.8
ingestedAt: '2026-10-16T19:46:24.380Z'
---

## Overview

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

bpf: Cancel special fields on map value recycle

Map update and delete paths currently call bpf_obj_free_fields() when a
value is being replaced or recycled. That makes field destruction depend
on the context of the update/delete operation. For tracing programs this
can include NMI context, where referenced kptr destructors, uptr
unpinning, and graph root destruction are not generally safe.

Introduce bpf_obj_cancel_fields() for the reusable-value path. It only
performs NMI-safe cleanup for timer, workqueue, and task_work fields.
Fields that need full destruction are left attached to the recycled value
and are destroyed by the final cleanup path instead.

Switch array and hashtab update/delete/recycle paths to this cancel
helper. Keep bpf_obj_free_fields() for final map destruction and for
bpf_mem_alloc destructors. Preallocated hashtabs do not have allocator
destructors, so teardown continues to walk the normal and extra elements
and fully destroy their fields.

This deliberately relaxes the eager-free semantics of map update/delete
for special fields. Programs that relied on a recycled map slot becoming
empty immediately after update/delete were relying on behavior that
cannot be implemented safely from every BPF execution context without
offloading arbitrary destructors.

There is a chance this change breaks programs making assumptions
regarding the eager freeing of fields. If so, we can relax semantics to
cancellation only when irqs_disabled() is true in the future. However,
theoretically, map values that get reused eagerly already have weaker
guarantees as parallel users can recreate freed fields before the new
element becomes visible again.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74314.json)