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CVE-2026-89523
wifi: mt76: mt7925: cancel pending mlo_pm_work
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-2026-89523 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
If the device is reset, suspended or unregistered within that window, the pending work can still run and access vif/bss data that may already be freed, or send MCU commands while the firmware is not available. Add cancel_delayed_work_sync(&dev->mlo_pm_work) in all relevant teardown and suspend paths: - mt7925_mac_reset_work() (chip reset recovery) - mt7925e_unregister_device() (PCIe unbind) - mt7925_pci_suspend() (PCIe bus suspend) - mt7925_suspend() (mac80211 suspend) - mt7925u_suspend() (USB bus / runtime suspend) This ensures the work is stopped before the device state becomes invalid.
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/mac.c
drivers/net/wireless/mediatek/mt76/mt7925/main.c
drivers/net/wireless/mediatek/mt76/mt7925/pci.c
drivers/net/wireless/mediatek/mt76/mt7925/usb.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 | 5be6d02837d4 |
| 6.15 | 7.2.4 | c5e073f2fbfd |
| 6.15 | 7.3 | 2889e84282dd |
| 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 leaves mlo_pm_work armed across local mt7925 teardown: chip-reset recovery, PCI unbind, and PCIe/mac80211/USB suspend. Those are host driver-lifecycle and power-management paths; over-the-air frames do not invoke them, matching other mt76 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 suspends, unbinds, or resets the device controls both sides and easily hits that window, with no attacker-uncontrollable race or heap layout.
- PR:LPrivileges required, low
- MLO association uses nl80211 connect (GENL_UNS_ADMIN_PERM/CAP_NET_ADMIN). Logged-in users can then suspend via logind/polkit or Android autosleep, and NetworkManager/Android Wi-Fi controls expose this without init-namespace root, so privileges are Low.
- UI:NUser interaction, none
- The attacker performs MLO association and the subsequent suspend, PCI/USB unbind, or reset 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 vif/bss_conf objects and the mt792x_dev-embedded delayed_work inside the mt7925 driver. It does not cross a VM, IOMMU, or sandbox security boundary.
- C:HConfidentiality impact, high
- PCI/USB unbind runs ieee80211_unregister_hw, which destroys the phy workqueue, then mt76_free_device() frees the mt792x_dev that embeds mlo_pm_work while the 5s timer still points at them. The worker also dereferences vif/bss_conf that remove_interface or change_vif_links may already have freed, enabling disclosure via heap reclaim.
- I:HIntegrity impact, high
- The dangling delayed_work timer can fire on a freed mt792x_dev after unbind, and mt7925_mlo_pm_iter can send MCU BSS_INFO_UPDATE through stale mconf/vif objects. That is a classic timer/workqueue UAF exploitable for writes and control-flow hijack, so Integrity is High.
- A:HAvailability impact, high
- The pending worker can WARN in __queue_work on a destroying phy workqueue, NULL-dereference a removed MLO link_conf, or issue MCU commands while firmware is reset or suspended, causing a kernel oops or panic. Any such crash is Availability High.