# CVE-2026-23175: net: cpsw: Execute ndo_set_rx_mode callback in a work queue

> A race condition in the Linux kernel CPSW network driver causes a kernel warning and potential instability when handling IPv6 multicast joins without the RTNL lock.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Feb 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-23175, DEBIAN-CVE-2026-23175, GHSA-6rr8-q652-pwgf, UBUNTU-CVE-2026-23175

## What is CVE-2026-23175?

CVE-2026-23175 is a high-severity vulnerability in Linux, published on 14 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

net: cpsw: 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/481
  RTNL: assertion failed at net/8021q/vlan_core.c (236)
  Modules linked in:
  CPU: 0 UID: 997 PID: 481 Comm: rpcbind Not tainted 6.19.0-rc7-next-20260130-yocto-standard+ #35 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+0x54/0x98
   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+0x0/0x54

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.

Please note: To reproduce this issue, I manually reverted the changes to
am335x-bone-common.dtsi from commit c477358e66a3 ("ARM: dts: am335x-bone:
switch to new cpsw switch drv") in order to revert to the legacy cpsw
driver.

## Which versions are affected by CVE-2026-23175?


## How do I fix CVE-2026-23175?

Apply the vendor's patch.

## Is CVE-2026-23175 being exploited?

There is no known exploitation of CVE-2026-23175 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23175 and fix it if it is affected.

What it is: CVE-2026-23175 is a high-severity vulnerability in Linux, published on 14 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23175 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-23175/ (Markdown: https://insights.sbomify.com/CVE-2026-23175/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23175
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23175
- OSV: https://osv.dev/vulnerability/CVE-2026-23175

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23175/
Summaries are generated and may contain mistakes; the official description above is the record.