CVE-2026-52971: net: ena: PHC: Fix potential use-after-free in get_timestamp

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-24 · updated 2026-10-19
Weakness: CWE-416

Description

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.

Affected products

Linux kernel: from 6.17 before 6.18.33; from 6.19 before 7.0.10; 7.1-rc1, 7.1-rc2, 7.1-rc3 — fixed in 6.18.33, 7.0.10

How to fix

Upgrade to a fixed version: Linux kernel 6.18.33, 7.0.10. Check the vendor advisory for mitigations.

References

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