GHSA-J7RH-WQHV-HC9P
Vulnerability from github – Published: 2026-10-06 09:31 – Updated: 2026-10-07 09:32In the Linux kernel, the following vulnerability has been resolved:
xfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()
syzbot reported a suspicious RCU usage warning in ip6_pkt_drop():
WARNING: suspicious RCU usage in ip6_pkt_drop include/net/addrconf.h:389 suspicious rcu_dereference_check() usage!
Call Trace: __in6_dev_get_safely include/net/addrconf.h:389 [inline] ip6_pkt_drop+0x596/0x610 net/ipv6/route.c:4620 ip6_pkt_discard+0x1c/0x30 net/ipv6/route.c:4651 xfrm_trans_reinject+0x324/0x630 net/xfrm/xfrm_input.c:806 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
When commit 4f4920669d21 ("xfrm: Reinject transport-mode packets through workqueue") converted xfrm_trans_reinject from a tasklet to a workqueue, the reinjection loop ceased running in softirq context. Workqueue workers run in process context where local_bh_disable() does not enter an RCU read-side critical section under CONFIG_PREEMPT_RCU.
Because finish callbacks (such as ip6_rcv_finish) expect to run under an RCU read lock (performing route lookups, l3mdev lookups, and accessing RCU-protected data structures), invoking them in workqueue context without rcu_read_lock() triggers RCU lockdep warnings.
Furthermore, packets queued to the workqueue via xfrm_trans_queue_net() may carry non-refcounted (noref) dst entries (e.g. from ip_route_input_noref). Additionally, on netdevice unregistration, dst_dev_put() replaces dst->dev with blackhole_netdev, so dst entries do not keep skb->dev alive while queued in the workqueue.
Fix these issues by: 1. Calling skb_dst_force(skb) in xfrm_trans_queue_net() while still in the caller's RCU section to ensure dst is reference-counted before queuing. 2. Holding a reference on skb->dev via dev_hold()/dev_put() across workqueue deferral so skb->dev remains valid during finish() callback processing. 3. Acquiring rcu_read_lock() around the finish callback invocation loop in xfrm_trans_reinject().
{
"affected": [],
"aliases": [
"CVE-2026-98369"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-06T09:18:31Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()\n\nsyzbot reported a suspicious RCU usage warning in ip6_pkt_drop():\n\n WARNING: suspicious RCU usage in ip6_pkt_drop\n include/net/addrconf.h:389 suspicious rcu_dereference_check() usage!\n\n Call Trace:\n __in6_dev_get_safely include/net/addrconf.h:389 [inline]\n ip6_pkt_drop+0x596/0x610 net/ipv6/route.c:4620\n ip6_pkt_discard+0x1c/0x30 net/ipv6/route.c:4651\n xfrm_trans_reinject+0x324/0x630 net/xfrm/xfrm_input.c:806\n process_one_work kernel/workqueue.c:3322 [inline]\n process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405\n worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486\n\nWhen commit 4f4920669d21 (\"xfrm: Reinject transport-mode packets through\nworkqueue\") converted xfrm_trans_reinject from a tasklet to a workqueue,\nthe reinjection loop ceased running in softirq context. Workqueue workers\nrun in process context where local_bh_disable() does not enter an RCU\nread-side critical section under CONFIG_PREEMPT_RCU.\n\nBecause finish callbacks (such as ip6_rcv_finish) expect to run under an\nRCU read lock (performing route lookups, l3mdev lookups, and accessing\nRCU-protected data structures), invoking them in workqueue context without\nrcu_read_lock() triggers RCU lockdep warnings.\n\nFurthermore, packets queued to the workqueue via xfrm_trans_queue_net()\nmay carry non-refcounted (noref) dst entries (e.g. from ip_route_input_noref).\nAdditionally, on netdevice unregistration, dst_dev_put() replaces dst-\u003edev\nwith blackhole_netdev, so dst entries do not keep skb-\u003edev alive while\nqueued in the workqueue.\n\nFix these issues by:\n1. Calling skb_dst_force(skb) in xfrm_trans_queue_net() while still in the\n caller\u0027s RCU section to ensure dst is reference-counted before queuing.\n2. Holding a reference on skb-\u003edev via dev_hold()/dev_put() across workqueue\n deferral so skb-\u003edev remains valid during finish() callback processing.\n3. Acquiring rcu_read_lock() around the finish callback invocation loop in\n xfrm_trans_reinject().",
"id": "GHSA-j7rh-wqhv-hc9p",
"modified": "2026-10-07T09:32:18Z",
"published": "2026-10-06T09:31:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98369"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0cda8273265d30cac6423834fd7d4acb75f04fdb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/41e47f1664be86c91326f0afe0504a1162d00907"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6601d91a85761f33351c71e04ec0bbd294ca07ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/664fc0941df7c1918b2cd4de6ee00469ba77d8e4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/68a317b4aec8ca1868a39d69e40f9e29baa4f40a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6eb3b071be8e260543c604550c54dac66e6b174b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d2f5082f9e84653fa1a9e8aebaaff23e688f5e19"
}
],
"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"
}
]
}
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