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CVE-2026-80936
wifi: mt76: mt7925: cancel mlo_pm_work on stop
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-80936 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
mt7925 queues mlo_pm_work with a 5 second delay during multi-link power-save setup and never cancels it on the stop path. If the device is torn down inside that window, the work outlives the teardown and its timer fires afterwards, trying to queue onto the workqueue that is already gone: workqueue: cannot queue mt7925_mlo_pm_work [mt7925_common] on wq phy0 WARNING: kernel/workqueue.c:2283 at __queue_work+0x59/0xa0, CPU#1: swapper/1/0 call_timer_fn+0x2a/0x140 __run_timers+0x203/0x330 run_timer_softirq+0x86/0xf0 mt7921 already has its own stop callback, so add one for mt7925 that cancels the work before calling mt792x_stop(). mt7925_ops backs both the PCIe and USB drivers, so this covers both.
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/wireless/mediatek/mt76/mt7925/main.c
- What this is
- MEDIATEK MT76 WIRELESS LAN DRIVERMAINTAINERS section matched on drivers/net/wireless/mediatek/mt76/ · linux-wireless@vger.kernel.org · Maintained
- Kernel module
- mt7925_common
Check it on the machine
grep -wE 'CONFIG_MT76_CORE|CONFIG_MT7925_COMMON|CONFIG_WLAN|CONFIG_WLAN_VENDOR_MEDIATEK' /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.
lsmod | grep -w mt7925_commonPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- ?
- not established - no Makefile entry for the affected file
- M
- a module where it is built at all; some flavours do not build it
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_MT76_CORE, CONFIG_MT7925_COMMON, CONFIG_WLAN, CONFIG_WLAN_VENDOR_MEDIATEK
- 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
- 2026-09-11 (37 days 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
- 0.17%, higher than 6.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- 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 |
|---|---|---|
| 6.15 | 6.18.50 | 304470333b7f |
| 6.15 | 7.2.4 | 9e20da749ad2 |
| 6.15 | 7.3 | 81faf578320d |
| 6.14.3 | 0 | 0 |
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
- The bug is in mt7925's mac80211 .stop callback, which leaves mlo_pm_work armed across local driver teardown (last wlan ndo_stop, PCI/USB unbind, USB disconnect, rmmod). Over-the-air frames never call ops->stop; this is a local interface/driver lifecycle path, matching other mt76 stop/cleanup UAFs.
- AC:LAttack complexity, low
- mt7925 queues mlo_pm_work with a fixed 5-second delay during MLO power-save setup; a local attacker who associates to a Wi-Fi 7 MLO AP and then immediately stops or unregisters the device controls both sides and easily hits that window, with no attacker-uncontrollable race or heap layout.
- PR:LPrivileges required, low
- Bringing the wireless interface down and driving nl80211 connect/disconnect uses GENL_UNS_ADMIN_PERM/CAP_NET_ADMIN, and ordinary NetworkManager/polkit or Android Wi-Fi controls expose that to unprivileged local users; per kernel guidance that is Low, not init-namespace root.
- UI:NUser interaction, none
- The attacker performs MLO association and the subsequent interface or driver teardown themselves; no separate victim action such as opening a file or mounting a filesystem is required.
- S:UScope, unchanged
- The use-after-free is of host kernel workqueue and mt792x_dev delayed_work state inside the mt7925 driver and does not cross a VM, IOMMU, or sandbox security boundary.
- C:HConfidentiality impact, high
- Unregister destroys the mac80211 phy workqueue and USB disconnect then mt76_free_device() frees the mt792x_dev that embeds mlo_pm_work while the 5s timer still points at them; a UAF of those objects enables disclosure via heap reclaim and is Confidentiality High per guidance.
- I:HIntegrity impact, high
- The dangling delayed_work timer can fire on a freed mt792x_dev (mt792xu_disconnect frees the device without cancelling mlo_pm_work), a classic timer/workqueue UAF that can be turned into writes and control-flow hijack after spraying; guidance rates Integrity High.
- A:HAvailability impact, high
- The pending timer calls __queue_work on a destroying phy workqueue (WARN in kernel/workqueue.c) and can oops when the timer runs against freed delayed_work, causing kernel warning, oops, or panic; any such crash is Availability High.