GHSA-34C4-H856-X83P
Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-23 15:33In 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.
{
"affected": [],
"aliases": [
"CVE-2026-74479"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T13:17:52Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: pktgen: fix proc entry use-after-free\n\npktgen_change_name() replaces pkt_dev-\u003eentry while holding t-\u003eif_lock.\npktgen_remove_device() removes the same entry before\n_rem_dev_from_if_list() takes that lock.\n\nThis allows the following interleaving:\n\n CPU 0 (NETDEV_CHANGENAME) CPU 1 (kpktgend)\n if_lock(t)\n proc_remove(pkt_dev-\u003eentry)\n proc_remove(pkt_dev-\u003eentry)\n pkt_dev-\u003eentry = proc_create_data(...)\n if_unlock(t)\n\nThe kthread can pass the stale proc_dir_entry to proc_remove() after the\nrename path has freed it. A reproducer with a widened race window reports:\n\n BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80\n Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67\n Call Trace:\n proc_remove+0x78/0x80\n pktgen_remove_device.isra.0+0x11c/0x4c0\n pktgen_thread_worker+0x1214/0x6bc0\n kthread+0x2c6/0x3b0\n Allocated by task 95:\n __proc_create+0x204/0x790\n proc_create_data+0x72/0xe0\n pktgen_thread_write+0xd61/0x1510\n Freed by task 28:\n kmem_cache_free+0xcb/0x3d0\n proc_free_inode+0x5b/0x80\n rcu_core+0x50a/0x1850\n The buggy address belongs to the object at ffff8881478fea00\n which belongs to the cache proc_dir_entry of size 192\n\nMove proc_remove() into the if_lock-protected list removal helper. Keep it\nbefore list_del_rcu() to preserve the ordering required by add_device().\nThe rename path must then finish replacing the entry before removal, or\nit observes that the device is no longer on the list.",
"id": "GHSA-34c4-h856-x83p",
"modified": "2026-08-23T15:33:02Z",
"published": "2026-08-15T15:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74479"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4ef801b838d85c0ea5852c50667f7344ce3b6cd0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/577443530cb592d5782a1f79847411a9363a65c8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/817ff6efdb7f484ea547218e11e17d8e43daa3b4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/82ed3db9269cb61e3c15bad2f6e221efce90e1e0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b006a5404470bd3eb2aa0425fc447183032047ef"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f85a58340b91f225de3299dfa782c6414098077c"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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Nomenclature
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