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CVE-2026-63832
wifi: mt76: add wcid publish check in mt76_sta_add
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-63832 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 7.1.3-1 | Update the kernel and reboot. Fixed in 7.1.3-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.3-1 | Update the kernel and reboot. Fixed in 7.1.3-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Since mt7925_mac_sta_add publishes wcid, add publish check in mt76_sta_add to avoid reinitializing the wcid->poll_list. Found dev->sta_poll_list corruption when using mt7925 and 7.1-rc4. According to the corruption information, prev->next was changed to itself. wlan0: disconnect from AP 90:fb:5d:94:8b:e3 for new auth to 90:fb:5d:94:8b:e2 wlan0: authenticate with 90:fb:5d:94:8b:e2 (local address=84:9e:56:9c:7e:6b) wlan0: send auth to 90:fb:5d:94:8b:e2 (try 1/3) slab kmalloc-8k start ffff8c80958a6000 pointer offset 4160 size 8192 list_add corruption. prev->next should be next (ffff8c808a7488f8), but was ffff8c80958a7040. (prev=ffff8c80958a7040). mt76_wcid_add_poll+0x95/0xd0 [mt76] mt7925_mac_add_txs.part.0+0xa5/0xe0 [mt7925_common] mt7925_rx_check+0xa7/0xc0 [mt7925_common] mt76_dma_rx_poll+0x50d/0x790 [mt76] mt792x_poll_rx+0x52/0xe0 [mt792x_lib]
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/mac80211.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
- mt76
Check it on the machine
grep -wE 'CONFIG_MT76_CORE|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 mt76Prints 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
- trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_MT76_CORE, 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
- 2026-07-19 (3 months 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
- 0.24%, higher than 13.5% 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 |
|---|---|---|
| 6.14 | 6.18.38 | 3c499851753a |
| 6.14 | 7.1.3 | 55e014aaec65 |
| 6.14 | 7.2 | 20b126920a25 |
| 6.12.13 | 0 | 0 |
| 6.13.2 | 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:AAttack vector, adjacent network
- The bug is reached through WiFi RX/TX-status DMA processing and station add during 802.11 association/roaming, both triggered by frames from a peer on the same wireless segment. Per kernel WiFi guidance, frame-driven driver bugs are Adjacent, not Network.
- AC:LAttack complexity, low
- An adjacent attacker can reliably create the race by sending deauth/association traffic to force sta re-add while flooding data frames to keep the RX poll path active; both sides of the race are attacker-influenced and repeatable.
- PR:NPrivileges required, none
- Exploitation requires no Linux privileges—only the ability to send 802.11 management/data frames as a nearby WiFi peer (rogue AP, deauth attacker, or associating client on AP mode), with no authentication to the victim host.
- UI:NUser interaction, none
- No victim user action is required beyond normal WiFi operation; deauth-forced roaming and automatic reassociation drive the vulnerable sta_add path without user interaction.
- S:UScope, unchanged
- Impact is kernel heap/list corruption within the same security authority; this is not a VM escape, IOMMU bypass, or cross-namespace boundary violation.
- C:HConfidentiality impact, high
- Reinitializing an embedded list_head while still linked corrupts kernel linked-list metadata in kmalloc-backed structures; list corruption is memory corruption that can be leveraged for arbitrary kernel memory disclosure.
- I:HIntegrity impact, high
- The corrupted doubly-linked list enables list-poisoning style arbitrary kernel writes and potential control-flow hijacking, not merely a bounded or transient modification.
- A:HAvailability impact, high
- The reproducer triggers kernel list_add corruption detection and crash; corrupted sta_poll_list integrity can cause kernel panic/oops during normal WiFi operation.