CVE-2025-39944

What it is

In the Linux kernel, the following vulnerability has been resolved: octeontx2-pf: Fix use-after-free bugs in otx2_sync_tstamp() The original code relies on cancel_delayed_work() in otx2_ptp_destroy(), which does not ensure that the delayed work item synctstamp_work has fully completed if it was already running. This leads to use-after-free scenarios where otx2_ptp is deallocated by otx2_ptp_destroy(), while synctstamp_work remains active and attempts to dereference otx2_ptp in otx2_sync_tstamp(). Furthermore, the synctstamp_work is cyclic, the likelihood of triggering the bug is nonnegligible. A typical race condition is illustrated below: CPU 0 (cleanup) | CPU 1 (delayed work callback) otx2_remove() | otx2_ptp_destroy() | otx2_sync_tstamp() cancel_delayed_work() | kfree(ptp) | | ptp = container_of(...); //UAF | ptp-> //UAF This is confirmed by a KASAN report: BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0 Write of size 8 at addr ffff88800aa09a18 by task bash/136 ... Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_report+0xcf/0x610 ? __run_timer_base.part.0+0x7d7/0x8c0 kasan_report+0xb8/0xf0 ? __run_timer_base.part.0+0x7d7/0x8c0 __run_timer_base.part.0+0x7d7/0x8c0 ? __pfx___run_timer_base.part.0+0x10/0x10 ? __pfx_read_tsc+0x10/0x10 ? ktime_get+0x60/0x140 ? lapic_next_event+0x11/0x20 ? clockevents_program_event+0x1d4/0x2a0 run_timer_softirq+0xd1/0x190 handle_softirqs+0x16a/0x550 irq_exit_rcu+0xaf/0xe0 sysvec_apic_timer_interrupt+0x70/0x80 </IRQ> ... Allocated by task 1: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x7f/0x90 otx2_ptp_init+0xb1/0x860 otx2_probe+0x4eb/0xc30 local_pci_probe+0xdc/0x190 pci_device_probe+0x2fe/0x470 really_probe+0x1ca/0x5c0 __driver_probe_device+0x248/0x310 driver_probe_device+0x44/0x120 __driver_attach+0xd2/0x310 bus_for_each_dev+0xed/0x170 bus_add_driver+0x208/0x500 driver_register+0x132/0x460 do_one_initcall+0x89/0x300 kernel_init_freeable+0x40d/0x720 kernel_init+0x1a/0x150 ret_from_fork+0x10c/0x1a0 ret_from_fork_asm+0x1a/0x30 Freed by task 136: kasan_save_stack+0x24/0x50 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3a/0x60 __kasan_slab_free+0x3f/0x50 kfree+0x137/0x370 otx2_ptp_destroy+0x38/0x80 otx2_remove+0x10d/0x4c0 pci_device_remove+0xa6/0x1d0 device_release_driver_internal+0xf8/0x210 pci_stop_bus_device+0x105/0x150 pci_stop_and_remove_bus_device_locked+0x15/0x30 remove_store+0xcc/0xe0 kernfs_fop_write_iter+0x2c3/0x440 vfs_write+0x871/0xd70 ksys_write+0xee/0x1c0 do_syscall_64+0xac/0x280 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the delayed work item is properly canceled before the otx2_ptp is deallocated. This bug was initially identified through static analysis. To reproduce and test it, I simulated the OcteonTX2 PCI device in QEMU and introduced artificial delays within the otx2_sync_tstamp() function to increase the likelihood of triggering the bug.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-10-04 08:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-19 21:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 7.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-10-04 08:15 UTC

Last modified

2026-10-19 21:10 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Modified

Affected

• Linux Kernel < 6.1.154
• Linux Kernel < 6.6.108
• Linux Kernel < 6.12.49
• Linux Kernel < 6.16.9
• Linux Kernel 6.17

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-39944.md and follow it. Check whether this project is affected by CVE-2025-39944. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

Copy as ticket · More options · Status badge