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CVE-2026-90353
wifi: mt76: mt7915: fix ext PHY use-after-free on register error path
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-90353 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
After mt7915_register_ext_phy() succeeded, a failure of the main PHY mt7915_init_debugfs() or mt7915_coredump_register() unwound through free_phy2, which called ieee80211_free_hw() on the ext PHY hw while it was still registered with mac80211, since mt76_unregister_device() only unregisters the main hw. Unregister the ext PHY (thermal + phy + hw) first and skip the redundant free.
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/mt7915/init.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
- mt7915e
Check it on the machine
grep -wE 'CONFIG_MT76_CORE|CONFIG_MT7915E|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 mt7915ePrints 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.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_MT76_CORE, CONFIG_MT7915E, 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
- 2026-09-17 (31 days ago)source
- CVSS
- 7.0 high
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 3.1% 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 |
|---|---|---|
| 5.19 | 6.1.188 | aa55bec92ba7 |
| 5.19 | 6.6.157 | ad706fcf6255 |
| 5.19 | 6.12.110 | 34058ad122f7 |
| 5.19 | 6.18.52 | a7fd3bae8e11 |
| 5.19 | 7.2.6 | 648f5f03ff50 |
| 5.19 | 7.3 | 15b960014f24 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 UAF is in mt7915_register_device()'s free_phy2 unwind, reached only from mt7915_pci_probe() and mt798x_wmac_probe() when mt7915_init_debugfs() or mt7915_coredump_register() fails after mt7915_register_ext_phy(); no 802.11 frame or nl80211 command supplies the triggering data.
- AC:HAttack complexity, high
- mt7915_init_debugfs() always returns 0, so the live branch is mt7915_coredump_register() failing its vzalloc of struct mt7915_crash_data after mt7915_alloc_ext_phy() produced phy2 (DBDC). That one-shot ENOMEM during pci/platform probe is not something an attacker can reliably force.
- PR:LPrivileges required, low
- After ieee80211_free_hw() on the still-registered ext PHY, mt76_unregister_device() drops only the main hw, leaving the ext wiphy, the default STA vif from ieee80211_register_hw(), and mt7915_thermal_ops (cdev->devdata = phy) reachable via nl80211 and thermal sysfs without init-namespace root or PCI bind capability.
- UI:NUser interaction, none
- No victim must mount media or open a file; once the probe unwind runs, udev, mac80211's leftover workqueue/inetaddr notifier, or the attacker’s own nl80211/thermal access touches the still-registered ext PHY.
- S:UScope, unchanged
- ieee80211_free_hw() frees the ext PHY's ieee80211_local/wiphy/sband while mac80211 still holds it; impact is host-kernel heap corruption, not a VM, IOMMU, or sandbox escape.
- C:HConfidentiality impact, high
- ieee80211_free_hw() kfree's the ext PHY's still-registered wiphy bands and wiphy_free()s the hw while cfg80211 and mt7915_thermal_get_cur_throttle_state() still dereference that phy via cdev->devdata, a UAF read primitive.
- I:HIntegrity impact, high
- The leftover ext-PHY object is written by mt7915_thermal_set_cur_throttle_state() (phy->cdev_state and mt7915_mcu_set_thermal_throttling) and by mac80211 workqueues never torn down by ieee80211_unregister_hw(), enabling UAF writes and control-flow hijack.
- A:HAvailability impact, high
- ieee80211_free_hw() without ieee80211_unregister_hw() leaves mac80211 workqueues, inetaddr notifiers, and the default wlan vif running against freed ieee80211_local, which oopses or panics on the next access.