linux-cve-announce - CVE-2026-23203: net: cpsw_new: Execute ndo_set_rx

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Message-ID: <2026021437-CVE-2026-23203-de1a@gregkh>
Date: Sat, 14 Feb 2026 17:29:00 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2026-23203: net: cpsw_new: Execute ndo_set_rx_mode callback in a work queue

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

net: cpsw_new: Execute ndo_set_rx_mode callback in a work queue

Commit 1767bb2d47b7 ("ipv6: mcast: Don't hold RTNL for
IPV6_ADD_MEMBERSHIP and MCAST_JOIN_GROUP.") removed the RTNL lock for
IPV6_ADD_MEMBERSHIP and MCAST_JOIN_GROUP operations. However, this
change triggered the following call trace on my BeagleBone Black board:
  WARNING: net/8021q/vlan_core.c:236 at vlan_for_each+0x120/0x124, CPU#0: rpcbind/496
  RTNL: assertion failed at net/8021q/vlan_core.c (236)
  Modules linked in:
  CPU: 0 UID: 997 PID: 496 Comm: rpcbind Not tainted 6.19.0-rc6-next-20260122-yocto-standard+ #8 PREEMPT
  Hardware name: Generic AM33XX (Flattened Device Tree)
  Call trace:
   unwind_backtrace from show_stack+0x28/0x2c
   show_stack from dump_stack_lvl+0x30/0x38
   dump_stack_lvl from __warn+0xb8/0x11c
   __warn from warn_slowpath_fmt+0x130/0x194
   warn_slowpath_fmt from vlan_for_each+0x120/0x124
   vlan_for_each from cpsw_add_mc_addr+0x54/0xd8
   cpsw_add_mc_addr from __hw_addr_ref_sync_dev+0xc4/0xec
   __hw_addr_ref_sync_dev from __dev_mc_add+0x78/0x88
   __dev_mc_add from igmp6_group_added+0x84/0xec
   igmp6_group_added from __ipv6_dev_mc_inc+0x1fc/0x2f0
   __ipv6_dev_mc_inc from __ipv6_sock_mc_join+0x124/0x1b4
   __ipv6_sock_mc_join from do_ipv6_setsockopt+0x84c/0x1168
   do_ipv6_setsockopt from ipv6_setsockopt+0x88/0xc8
   ipv6_setsockopt from do_sock_setsockopt+0xe8/0x19c
   do_sock_setsockopt from __sys_setsockopt+0x84/0xac
   __sys_setsockopt from ret_fast_syscall+0x0/0x5

This trace occurs because vlan_for_each() is called within
cpsw_ndo_set_rx_mode(), which expects the RTNL lock to be held.
Since modifying vlan_for_each() to operate without the RTNL lock is not
straightforward, and because ndo_set_rx_mode() is invoked both with and
without the RTNL lock across different code paths, simply adding
rtnl_lock() in cpsw_ndo_set_rx_mode() is not a viable solution.

To resolve this issue, we opt to execute the actual processing within
a work queue, following the approach used by the icssg-prueth driver.

The Linux kernel CVE team has assigned CVE-2026-23203 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.17 with commit 1767bb2d47b715a106287a8f963d9ec6cbab4e69 and fixed in 6.18.10 with commit d5b3a669866977dc87fd56fcf00a70df1536d258
	Issue introduced in 6.17 with commit 1767bb2d47b715a106287a8f963d9ec6cbab4e69 and fixed in 6.19 with commit c0b5dc73a38f954e780f93a549b8fe225235c07a

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-23203
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/ti/cpsw_new.c
	drivers/net/ethernet/ti/cpsw_priv.h

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/d5b3a669866977dc87fd56fcf00a70df1536d258
	https://git.kernel.org/stable/c/c0b5dc73a38f954e780f93a549b8fe225235c07a