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CVE-2026-74554
wifi: ath12k: fix out-of-bounds clear_bit in ath12k_mac_dp_peer_cleanup()
Published 2026-08-15 (2 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-2026-74554 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 | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
ath12k_mac_dp_peer_cleanup() clears the ML peer ID slot on the free_ml_peer_id_map bitmap by indexing it with dp_peer->peer_id. That is wrong: dp_peer->peer_id for an MLO peer always carries the ATH12K_PEER_ML_ID_VALID bit (BIT(13)), so clear_bit() is invoked with index >= 0x2000, which is far outside the bitmap of ATH12K_MAX_MLO_PEERS (256) bits and corrupts memory adjacent to ah->free_ml_peer_id_map. The intended bitmap entry also never gets cleared, so subsequent ath12k_peer_ml_alloc() calls eventually run out of IDs. The ID without the VALID bit is what ath12k_peer_ml_alloc() returned and is stored in ahsta->ml_peer_id. Use that instead. While there, also reset ahsta->ml_peer_id to ATH12K_MLO_PEER_ID_INVALID so the bitmap and ahsta->ml_peer_id stay in sync. Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3
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/ath/ath12k/mac.c
- What this is
- QUALCOMM ATH12K WIRELESS DRIVERMAINTAINERS section matched on drivers/net/wireless/ath/ath12k/ · linux-wireless@vger.kernel.org · Supported
- Kernel module
- ath12k
Check it on the machine
grep -wE 'CONFIG_ATH12K|CONFIG_WLAN|CONFIG_WLAN_VENDOR_ATH' /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 ath12kPrints 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?
- 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
- ?
- 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_ATH12K, CONFIG_WLAN, CONFIG_WLAN_VENDOR_ATH
- 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
- 2026-08-15 (2 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
- 0.34%, higher than 26.0% 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 |
|---|---|---|
| 7.0 | 7.1.8 | 234b5cb81e6f |
| 7.0 | 7.2 | 47abd2ca2815 |
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 in ath12k WiFi 7 MLO peer cleanup during firmware crash recovery; an adjacent attacker associates as an MLO client (or runs a malicious MLO AP) over 802.11, creating dp_peers whose peer_id includes BIT(13), then firmware recovery invokes ath12k_mac_dp_peer_cleanup().
- AC:LAttack complexity, low
- Once an MLO peer exists, recovery deterministically calls clear_bit() with index >=0x2000 on every cleanup; the attacker controls association and can repeatedly induce or wait for firmware crash/recovery (MHI RDDM) without depending on uncontrollable timing or layout.
- PR:NPrivileges required, none
- Exploitation requires only wireless association and firmware recovery on a host running ath12k; the remote attacker needs no local account, shell access, or Linux capabilities on the victim system.
- UI:NUser interaction, none
- On an ath12k AP the vulnerable recovery path runs without any action by the device operator beyond normal AP operation; the attacker triggers the condition solely by wireless association and crash/recovery events.
- S:UScope, unchanged
- The out-of-bounds clear_bit corrupts kernel memory in ath12k_hw/dp_hw adjacent to free_ml_peer_id_map; impact stays within kernel/driver context and does not by itself cross VM, container, or IOMMU security boundaries.
- C:HConfidentiality impact, high
- clear_bit() with peer_id>=0x2000 writes outside the 256-bit free_ml_peer_id_map into the adjacent dp_peers[] RCU pointer table, corrupting kernel pointers that can be dereferenced later for arbitrary kernel memory read primitives.
- I:HIntegrity impact, high
- The out-of-bounds atomic bit-clear is a kernel memory write that corrupts dp_peers[] entries used on datapath RX/TX, enabling control of freed/corrupted objects and potential arbitrary code execution, not merely a benign crash.
- A:HAvailability impact, high
- Corrupted dp_peers pointers during recovery can cause kernel oops/panic on subsequent datapath use, and the bitmap slot is never freed so ath12k_peer_ml_alloc() exhausts MLO peer IDs, denying further MLO associations (DoS).