CVE-2026-99053 is a vulnerability in Linux Kernel
Published on October 23, 2026
tipc: hold a reference to nodes found by link name
In the Linux kernel, the following vulnerability has been resolved:
tipc: hold a reference to nodes found by link name
tipc_node_find_by_name() returns a node after dropping its RCU read lock
without taking a reference. The LINK_SET, LINK_GET and LINK_RESET_STATS
handlers then lock and access the node, racing with timer-driven cleanup of
a down peer. Generic netlink serialization does not exclude the node
timer.
The following interleaving can leave a handler using a freed node:
CPU 0: find the node under RCU and release the node read lock
CPU 1: tipc_node_timeout() clears the links and unlinks the down node
CPU 1: drop the list and timer references, queuing tipc_node_free()
CPU 0: leave the RCU read-side critical section
CPU 1: complete the grace period and free the node
CPU 0: acquire the node lock through the stale pointer
LINK_SET also uses the node's media address after releasing the node lock,
when passing queued packets to tipc_bearer_xmit().
KASAN on v7.3-rc5 reported:
BUG: KASAN: slab-use-after-free in _raw_read_lock_bh
Write of size 4 at addr ffff88807e06f008 by task poc/92
Call Trace:
_raw_read_lock_bh kernel/locking/spinlock.c:287
tipc_nl_node_set_link net/tipc/node.c:2475
genl_family_rcv_msg_doit net/netlink/genetlink.c:1114
genl_rcv_msg net/netlink/genetlink.c:1209
netlink_rcv_skb net/netlink/af_netlink.c:2575
Allocated by task 0:
tipc_node_create net/tipc/node.c:539
tipc_node_check_dest net/tipc/node.c:1196
tipc_disc_rcv net/tipc/discover.c:252
Freed by task 92:
kfree mm/slub.c:6801
rcu_core kernel/rcu/tree.c:2919
Last potentially related work creation:
__call_rcu_common.constprop.0 kernel/rcu/tree.c:3181
tipc_node_timeout net/tipc/node.c:814
Acquire a reference to the selected node with kref_get_unless_zero() before
leaving RCU, returning NULL if the node has already been released. Release
that reference on every caller exit after the last node access, including
transmission in LINK_SET. Keep the existing link lookup order and locking
so concurrent link removal still takes the existing error paths.
Products Associated with CVE-2026-99053
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Affected Versions
Linux:- Version 6a939f365bdb03a74b4617bdb4402fc08da088b9 and below b60259d4047fbb735476c729dcf9306a038b6110 is affected.
- Version 6a939f365bdb03a74b4617bdb4402fc08da088b9 and below f17e70206a1e763fcca2578a8db3c4eed0f843a9 is affected.
- Version 6a939f365bdb03a74b4617bdb4402fc08da088b9 and below 1428c5f1d346a2e1ac9156713975a72246957009 is affected.
- Version 6a939f365bdb03a74b4617bdb4402fc08da088b9 and below 3c3b308ee6e25729a6cf09b69cdd0e093220d40b is affected.
- Version 6a939f365bdb03a74b4617bdb4402fc08da088b9 and below 17e73bae400f6a434dc006e3bee92c94cf781954 is affected.
- Version 4.19 is affected.
- Before 4.19 is unaffected.
- Version 6.6.160, <= 6.6.* is unaffected.
- Version 6.12.113, <= 6.12.* is unaffected.
- Version 6.18.57, <= 6.18.* is unaffected.
- Version 7.2.11, <= 7.2.* is unaffected.
- Version 7.3, <= * is unaffected.