---
id: CVE-2026-52971
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: ena: PHC: Fix potential use-after-free in get_timestamp

  Move the phc->active check and resp pointer assignment to after
  acquiring the spinlock
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: ena: PHC: Fix potential use-after-free in get_timestamp

  Move the phc->active check and resp pointer assignment to after
  acquiring the spinlock. Previously, phc->a…
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'
published: '2026-06-24'
updated: '2026-07-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52971'
references:
  - url: 'https://git.kernel.org/stable/c/95e8ae9af2a61b4e72f5c585bf4c7d8aaf2a2c98'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ca9ed40f28949353911dcb524ff8fff2f3409c97'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e42c755582f0960e684298762f0ab927b3778376'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52971.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-52971'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492436'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-52971'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52971'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026062439-CVE-2026-52971-0bf1@gregkh/T
  - url: 'https://access.redhat.com/errata/RHSA-2026:68507'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68570'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00133
epssPercentile: 0.02288
ingestedAt: '2026-07-11T13:13:25.101Z'
vendor: Red Hat
product: Red Hat Enterprise Linux BaseOS (v. 10)
affected:
  - enterprise_linux 9
  - enterprise_linux_appstream_v_10
  - enterprise_linux_appstream_v_9
  - enterprise_linux_baseos_v_10
  - enterprise_linux_baseos_v_9
  - enterprise_linux_codeready_linux_builder_v_10
  - enterprise_linux_codeready_linux_builder_v_9
  - enterprise_linux_real_time_for_nfv_v_10
  - enterprise_linux_real_time_for_nfv_v_9
  - enterprise_linux_real_time_v_10
  - enterprise_linux_real_time_v_9
patched:
  - enterprise_linux_appstream_v_10
  - enterprise_linux_appstream_v_9
  - enterprise_linux_baseos_v_10
  - enterprise_linux_baseos_v_9
  - enterprise_linux_codeready_linux_builder_v_10
  - enterprise_linux_codeready_linux_builder_v_9
  - enterprise_linux_real_time_for_nfv_v_10
  - enterprise_linux_real_time_for_nfv_v_9
  - enterprise_linux_real_time_v_10
  - enterprise_linux_real_time_v_9
cwe:
  - CWE-825
scores:
  nvd: 7.8
  vendor: 7
---

## Overview

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

net: ena: PHC: Fix potential use-after-free in get_timestamp

Move the phc->active check and resp pointer assignment to after
acquiring the spinlock. Previously, phc->active was checked without
holding the lock, and resp was cached from ena_dev->phc.virt_addr
before the lock was acquired.

If ena_com_phc_destroy() runs between the lockless active check and
the lock acquisition, it sets active=false, releases the lock, frees
the DMA memory, and sets virt_addr=NULL. The get_timestamp path would
then read a NULL virt_addr and dereference it.

With both the active check and the pointer read under the lock,
destroy cannot free the memory while get_timestamp is using it.

## Remediation

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

## Vendor advisories

- **RHSA-2026:68507** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68507)
- **RHSA-2026:68570** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68570)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52971.json)