Look up another CVE · open CVE-2026-72109 in the interactive tracker
CVE-2026-72109
net: sparx5: unregister blocking notifier on init failure
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-72109 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
sparx5_register_notifier_blocks() registers the switchdev blocking notifier before allocating the ordered workqueue. If the workqueue allocation fails, the error path unregisters the switchdev and netdevice notifiers, but leaves the blocking notifier registered. Add a separate error label for the workqueue allocation failure path and unregister the switchdev blocking notifier there.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c
- What this is
- NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/ · netdev@vger.kernel.org · Maintained
- Kernel module
- none to look for. The file would have gone into sparx5_switch, and Debian does not compile it into that module, so finding sparx5_switch in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_NET_VENDOR_MICROCHIP|CONFIG_SPARX5_SWITCH' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_ETHERNET, CONFIG_NET_VENDOR_MICROCHIP, CONFIG_SPARX5_SWITCH
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 5.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.14 | 5.15.212 | fbc65b17508e |
| 5.14 | 6.1.178 | e5afc6d3fabd |
| 5.14 | 6.6.145 | cf419c869e0d |
| 5.14 | 6.12.97 | d6084c47389f |
| 5.14 | 6.18.40 | 8a3c44a00317 |
| 5.14 | 7.1.5 | 17f113e7b622 |
| 5.14 | 7.2 | 483be61b4a9a |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Exploitation reaches sparx5_switchdev_blocking_event through global switchdev blocking notifier callbacks fired by local bridge/VLAN/MDB configuration via rtnetlink, not by processing remote packets on Sparx5 switch ports.
- AC:LAttack complexity, low
- After a sparx5 probe workqueue ENOMEM leaves the blocking notifier registered and devm frees sparx5, an attacker can reliably trigger call_switchdev_blocking_notifiers with ordinary bridge or VLAN netlink operations without uncontrollable races.
- PR:LPrivileges required, low
- Triggering switchdev blocking events requires CAP_NET_ADMIN for bridge/VLAN changes; unprivileged users can obtain that capability in user/network namespaces and invoke the global notifier chain from their own bridge configuration.
- UI:NUser interaction, none
- No victim interaction is required beyond the attacker performing network administration operations; no user must open files, mount filesystems, or click anything to reach the stale notifier callback.
- S:UScope, unchanged
- The use-after-free corrupts kernel memory within the same kernel security authority on Sparx5/LAN969x switch platforms, enabling local privilege escalation but not VM escape or other cross-authority boundary bypass by itself.
- C:HConfidentiality impact, high
- The leaked switchdev_blocking_nb remains on a global chain after devm frees the containing sparx5 structure; sparx5_switchdev_blocking_event dereferences it via container_of, creating a use-after-free that can disclose kernel memory.
- I:HIntegrity impact, high
- UAF callbacks such as sparx5_handle_port_vlan_add and MDB handlers dereference freed sparx5 state and can write through sparx5_mact_learn and related hardware programming, enabling memory corruption and potential arbitrary code execution.
- A:HAvailability impact, high
- Dereferencing freed notifier_block and sparx5 structures during global switchdev blocking events can cause kernel oops, panic, or hang, disrupting availability on enterprise, industrial, and automotive Sparx5-managed switch systems.