---
id: CVE-2026-99053
title: 'tipc: hold a reference to nodes found by link name'
summary: |-
  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, …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 <
    b60259d4047fbb735476c729dcf9306a038b6110
  - >-
    Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 <
    f17e70206a1e763fcca2578a8db3c4eed0f843a9
  - >-
    Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 <
    1428c5f1d346a2e1ac9156713975a72246957009
  - >-
    Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 <
    3c3b308ee6e25729a6cf09b69cdd0e093220d40b
  - >-
    Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 <
    17e73bae400f6a434dc006e3bee92c94cf781954
  - Linux 4.19
published: '2026-10-23'
updated: '2026-10-24'
sourceUpdated: '2026-10-24T14:10:13.569Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99053'
references:
  - url: 'https://git.kernel.org/stable/c/b60259d4047fbb735476c729dcf9306a038b6110'
  - url: 'https://git.kernel.org/stable/c/f17e70206a1e763fcca2578a8db3c4eed0f843a9'
  - url: 'https://git.kernel.org/stable/c/1428c5f1d346a2e1ac9156713975a72246957009'
  - url: 'https://git.kernel.org/stable/c/3c3b308ee6e25729a6cf09b69cdd0e093220d40b'
  - url: 'https://git.kernel.org/stable/c/17e73bae400f6a434dc006e3bee92c94cf781954'
tags:
  - cve.org
epss: 0.00209
epssPercentile: 0.10495
ingestedAt: '2026-10-23T13:24:55.521Z'
---

## Overview

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.

## Affected

- `Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 < b60259d4047fbb735476c729dcf9306a038b6110`
- `Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 < f17e70206a1e763fcca2578a8db3c4eed0f843a9`
- `Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 < 1428c5f1d346a2e1ac9156713975a72246957009`
- `Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 < 3c3b308ee6e25729a6cf09b69cdd0e093220d40b`
- `Linux >= 6a939f365bdb03a74b4617bdb4402fc08da088b9 < 17e73bae400f6a434dc006e3bee92c94cf781954`
- `Linux 4.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.