CVE-2026-98369 is a vulnerability in Linux Kernel
Published on October 6, 2026
xfrm: add missing rcu_read_lock(), skb_dst_force() and dev_hold() for xfrm_trans_reinject()
In 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().
Products Associated with CVE-2026-98369
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Affected Versions
Linux:- Version 7d98b26684cb2390729525b341ea099f0badbe18 and below 41e47f1664be86c91326f0afe0504a1162d00907 is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below 6601d91a85761f33351c71e04ec0bbd294ca07ce is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below 0cda8273265d30cac6423834fd7d4acb75f04fdb is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below 68a317b4aec8ca1868a39d69e40f9e29baa4f40a is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below 6eb3b071be8e260543c604550c54dac66e6b174b is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below 664fc0941df7c1918b2cd4de6ee00469ba77d8e4 is affected.
- Version 4f4920669d21e1060b7243e5118dc3b71ced1276 and below d2f5082f9e84653fa1a9e8aebaaff23e688f5e19 is affected.
- Version f520075da484306bbb8425afd2c42404ba74816f is affected.
- Version 130d9e5017ade1b81d16783563edb38c12a2eab7 is affected.
- Version 5.15.75 and below 5.15.222 is affected.
- Version 5.19.17 and below 5.20 is affected.
- Version 6.0.3 and below 6.1 is affected.
- Version 6.1 is affected.
- Before 6.1 is unaffected.
- Version 5.15.222, <= 5.15.* is unaffected.
- Version 6.1.189, <= 6.1.* is unaffected.
- Version 6.6.158, <= 6.6.* is unaffected.
- Version 6.12.112, <= 6.12.* is unaffected.
- Version 6.18.54, <= 6.18.* is unaffected.
- Version 7.2.8, <= 7.2.* is unaffected.
- Version 7.3-rc4, <= * is unaffected.