Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-06-24T00:00:00 kernel: net: ena: PHC: Fix potential use-after-free in get_timestamp 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-825

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.

A flaw was found in the Linux kernel's Elastic Network Adapter (ENA) driver, specifically within the Precision Time Protocol Hardware Clock (PHC) timestamp retrieval function. A race condition exists where the `get_timestamp` function could attempt to access memory that has already been freed by the `ena_com_phc_destroy` function. This use-after-free vulnerability can lead to a NULL pointer dereference, potentially causing a system crash and resulting in a Denial of Service (DoS).

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-52971 https://nvd.nist.gov/vuln/detail/CVE-2026-52971 https://lore.kernel.org/linux-cve-announce/2026062439-CVE-2026-52971-0bf1@gregkh/T