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CVE-2026-90380
wifi: mt76: mt792x: fix use-after-free in mt76_rx_poll_complete
Published 2026-09-17 (31 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-2026-90380 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 | 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
A use-after-free issue occurs in mt76_rx_poll_complete due to a race condition. The STA has already been removed, but the rx_status still had a pointer to the wcid in the STA. Set the links' wcid pointers to be NULL for a MLD in mt7925_sta_pre_rcu_remove() BUG: KASAN: invalid-access in mt76_rx_poll_complete+0x280/0x470 Call trace: dump_backtrace+0xec/0x128 show_stack+0x18/0x28 dump_stack_lvl+0x40/0xc8 print_report+0x1b8/0x710 kasan_report+0xe0/0x144 do_bad_area+0x120/0x260 do_tag_check_fault+0x20/0x34 do_mem_abort+0x54/0xa8 el1_abort+0x3c/0x5c el1h_64_sync_handler+0x40/0xcc el1h_64_sync+0x7c/0x80 mt76_rx_poll_complete+0x280/0x470 mt76_dma_rx_poll+0x114/0x51c mt792x_poll_rx+0x60/0xf8 napi_threaded_poll_loop+0xe0/0x450 napi_threaded_poll+0x80/0x9c kthread+0x11c/0x158 ret_from_fork+0x10/0x20
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
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- ?
- 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
- 2026-09-17 (31 days ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.31%, higher than 22.6% 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 |
|---|---|---|
| 6.7 | 6.12.110 | aaf414bf81ab |
| 6.7 | 6.18.57 | 2aa3d3b9fac9 |
| 6.7 | 7.2.6 | b250943f3f83 |
| 6.7 | 7.3 | 217f9e7bb025 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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:AAttack vector, adjacent network
- An 802.11be MLO peer's frames are DMA'd into mt792x_poll_rx→mt76_dma_rx_poll→mt7925_queue_rx_skb→mt7925_mac_fill_rx, which stores status->wcid from MT_RXD1_NORMAL_WLAN_IDX via mt792x_rx_get_wcid(); those bytes arrive over WiFi radio, which is adjacent rather than a routable IP transport.
- AC:LAttack complexity, low
- The attacker drives both sides: data frames on a non-default MLO link keep mt76_rx_poll_complete using a secondary mt792x_link_sta.wcid that mt76_sta_pre_rcu_remove never NULLs, while a deauth/disassoc runs __sta_info_destroy. mt7925_mac_link_sta_remove then sleeps in MCU commands before clearing that idx, so the race is attacker-retryable.
- PR:NPrivileges required, none
- mt76_rx_poll_complete and ieee80211_rx_mgmt_deauth→ieee80211_set_disassoc run on the WiFi RX path with no Linux credential or capability check; a radio-range MLO AP sending deauth plus data is enough, with no local account on the mt7925 client.
- UI:NUser interaction, none
- Once the mt7925 station VIF is already in an MLO association (WIPHY_FLAG_SUPPORTS_MLO is set only for NL80211_IFTYPE_STATION), the attacker triggers STA teardown and the concurrent RX by transmitting; no mount, click, or other victim action is required at exploit time.
- S:UScope, unchanged
- The UAF is of the mt792x_link_sta.wcid published in dev->wcid[] and later used in mt76_check_sta/mt76_rx_complete inside this host kernel; it does not cross a VM, IOMMU, or guest/host boundary.
- C:HConfidentiality impact, high
- After the MLD STA is freed, mt76_check_sta and mt76_rx_convert still dereference status->wcid (wcid->sta, wcid->link_valid/link_id, wcid_to_sta()) from skb->cb, a use-after-free of the attacker-reallocatable mt792x_link_sta that enables arbitrary kernel reads.
- I:HIntegrity impact, high
- The same dangling wcid is written in mt76_check_sta (ewma_signal_add, wcid->inactive_count, PS flag bits) and in mt76_check_ccmp_pn (memcpy into wcid->rx_key_pn[] from the frame IV), giving a kernel write primitive through the freed mt792x_link_sta.
- A:HAvailability impact, high
- KASAN already reports invalid-access in mt76_rx_poll_complete when the RX NAPI uses the freed wcid after STA removal; that use-after-free oopses or panics the kernel even without a full exploit.