CVE-2025-39855

/// Technical description

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

ice: fix NULL access of tx->in_use in ice_ptp_ts_irq

The E810 device has support for a "low latency" firmware interface to

access and read the Tx timestamps. This interface does not use the standard

Tx timestamp logic, due to the latency overhead of proxying sideband

command requests over the firmware AdminQ.

The logic still makes use of the Tx timestamp tracking structure,

ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx

timestamps complete.

Unfortunately, the ice_ptp_ts_irq() function does not check if the tracker

is initialized before its first access. This results in NULL dereference or

use-after-free bugs similar to the following:

[245977.278756] BUG: kernel NULL pointer dereference, address: 0000000000000000

[245977.278774] RIP: 0010:_find_first_bit+0x19/0x40

[245977.278796] Call Trace:

[245977.278809] ? ice_misc_intr+0x364/0x380 [ice]

This can occur if a Tx timestamp interrupt races with t

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References