CVE-2026-74479

Status: UPDATED  |  Advisory ID: CVE-2026-74479

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

net: pktgen: fix proc entry use-after-free

pktgen_change_name() replaces pkt_dev->entry while holding t->if_lock.

pktgen_remove_device() removes the same entry before

_rem_dev_from_if_list() takes that lock.

This allows the following interleaving:

CPU 0 (NETDEV_CHANGENAME) CPU 1 (kpktgend)

if_lock(t)

proc_remove(pkt_dev->entry)

proc_remove(pkt_dev->entry)

pkt_dev->entry = proc_create_data(...)

if_unlock(t)

The kthread can pass the stale proc_dir_entry to proc_remove() after the

rename path has freed it. A reproducer with a widened race window reports:

BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80

Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67

Call Trace:

proc_remove+0x78/0x80

pktgen_remove_device.isra.0+0x11c/0x4c0

pktgen_thread_worker+0x1214/0x6bc0

kthread+0x2c6/0x3b0

Allocated by task 95:

__proc_create+0x204/0x790

proc_create_data+0x72/0xe0

pktgen_thread_write+0xd61/0x1510

Freed by task 28:

kmem_cache_free+0xcb/0x3d0

proc_free_inode+0x5b/0x80

rcu_core+0x50a/0x1850

The buggy address belongs to the object at ffff8881478fea00

which belongs to the cache proc_dir_entry of size 192

Move proc_remove() into the if_lock-protected list removal helper. Keep it

before list_del_rcu() to preserve the ordering required by add_device().

The rename path must then finish replacing the entry before removal, or

it observes that the device is no longer on the list. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References