CVE-2026-74479

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

State: Published
Severity: 7.8 High
Published: Aug 15, 2026
Updated: Oct 16, 2026
Reserved: Aug 15, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 82ed3db9269cb61e3c15bad2f6e221efce90e1e0Affected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4Affected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4Affected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 577443530cb592d5782a1f79847411a9363a65c8Affected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before f85a58340b91f225de3299dfa782c6414098077cAffected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 4ef801b838d85c0ea5852c50667f7344ce3b6cd0Affected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before b006a5404470bd3eb2aa0425fc447183032047efAffected 39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 817ff6efdb7f484ea547218e11e17d8e43daa3b4Affected
LinuxLinux	2.6.22Affected before 2.6.22Not affected 5.10.266 through 5.10.Not affected 5.15.217 through 5.15.Not affected 6.1.184 through 6.1.Not affected 6.6.153 through 6.6.Not affected 6.12.105 through 6.12.Not affected 6.18.44 through 6.18.Not affected 7.1.8 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 82ed3db9269cb61e3c15bad2f6e221efce90e1e0Affected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4Affected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4Affected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 577443530cb592d5782a1f79847411a9363a65c8Affected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before f85a58340b91f225de3299dfa782c6414098077cAffected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 4ef801b838d85c0ea5852c50667f7344ce3b6cd0Affected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before b006a5404470bd3eb2aa0425fc447183032047efAffected
39df232f1a9ba48d41c68ee7d4046756e709cf91 to before 817ff6efdb7f484ea547218e11e17d8e43daa3b4Affected

LinuxLinux

2.6.22Affected
before 2.6.22Not affected
5.10.266 through 5.10.*Not affected
5.15.217 through 5.15.*Not affected
6.1.184 through 6.1.*Not affected
6.6.153 through 6.6.*Not affected
6.12.105 through 6.12.*Not affected
6.18.44 through 6.18.*Not affected
7.1.8 through 7.1.*Not affected
7.2 and laterNot affected

References

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