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CVE-2026-97442
wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi
Published 2026-09-24 (24 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-2026-97442 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
In certain cases, hardware might provide packets with a length greater than the maximum native Wi-Fi header length. This can lead to accessing and modifying fields in the header within the ath11k_dp_rx_h_undecap_nwifi() function for the DP_RX_DECAP_TYPE_NATIVE_WIFI decap type and potentially result in invalid data access and memory corruption. Kernel stack is corrupted in: ath11k_dp_rx_h_undecap+0x6b0/0x6b0 [ath11k] Call trace: ath11k_dp_rx_h_mpdu+0x0/0x2e8 [ath11k] ath11k_dp_rx_h_mpdu+0x1e0/0x2e8 [ath11k] ath11k_dp_rx_wbm_err+0x1e0/0x450 [ath11k] ath11k_dp_rx_process_wbm_err+0x2fc/0x460 [ath11k] ath11k_dp_service_srng+0x2e0/0x348 [ath11k] Add a sanity check before processing the SKB to prevent invalid data access in the undecap native Wi-Fi function for the DP_RX_DECAP_TYPE_NATIVE_WIFI decap type. This adapted from the discussion/patch of the ath12k driver [1]. Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-04685-QCAHSPSWPL_V1_V2_SILICONZ_IOE-1
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/ath11k/dp_rx.c
- What this is
- QUALCOMM ATHEROS ATH11K WIRELESS DRIVERMAINTAINERS section matched on drivers/net/wireless/ath/ath11k/ · linux-wireless@vger.kernel.org · Supported
- Kernel module
- ath11k
Check it on the machine
grep -wE 'CONFIG_ATH11K|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 ath11kPrints 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
- 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_ATH11K, 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
- 2026-09-24 (24 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
- 0.25%, higher than 15.8% 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 |
|---|---|---|
| 5.7 | 6.1.189 | 958cf3696ddc |
| 5.7 | 6.6.158 | b4ef30f1d107 |
| 5.7 | 6.12.111 | 1c0a13be76db |
| 5.7 | 6.18.53 | 00738665c875 |
| 5.7 | 7.2 | 6b471e9aefee |
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:AAttack vector, adjacent network
- The attacker-controlled bytes are the 802.11 frame_control of a native-WiFi MSDU that reaches ath11k_dp_rx_h_undecap_nwifi() via ath11k_pcic_ext_grp_napi_poll/ath11k_ahb_ext_grp_napi_poll → ath11k_dp_service_srng → ath11k_dp_rx_process_wbm_err → ath11k_dp_rx_wbm_err → ath11k_dp_rx_h_mpdu → ath11k_dp_rx_h_undecap. That is over-the-air WiFi, not a routable IP protocol.
- AC:LAttack complexity, low
- ieee80211_hdrlen() is a function of frame_control bits the attacker sets. A 4-address QoS data A-MSDU gives hdr_len 32 (36 with Order), which exceeds decap_hdr[DP_MAX_NWIFI_HDR_LEN] (30). ath11k_frame_mode defaults to ATH11K_HW_TXRX_NATIVE_WIFI, and the attacker retransmits until a non-first subframe takes memcpy(decap_hdr, hdr, hdr_len). No uninfluenced device state.
- PR:NPrivileges required, none
- ath11k_dp_rx_h_null_q_desc() handles WBM DESC_ADDR_ZERO MSDUs with no REO peer/TID queue and still calls ath11k_dp_rx_h_mpdu(); a peer miss falls back to the RX-descriptor encrypt type. That NAPI path has no uid or capability check, so an unauthenticated nearby transmitter whose frame passes the hardware RA filter is enough.
- UI:NUser interaction, none
- Once the ath11k netdev is up, the injected native-WiFi MSDU is processed in NAPI by ath11k_dp_rx_wbm_err or ath11k_dp_rx_process_msdu. No mount, click, pairing, or other victim action is required at trigger time.
- S:UScope, unchanged
- The overflow is the 30-byte decap_hdr stack array inside ath11k_dp_rx_h_undecap_nwifi() in the host kernel. It does not escape a VM, bypass the IOMMU, or otherwise leave this security authority.
- C:HConfidentiality impact, high
- After the overflow, memcpy(skb_push(msdu, hdr_len), decap_hdr, hdr_len) copies the extra 2–6 bytes plus adjacent kernel stack into the skb that ath11k_dp_rx_deliver_msdu() hands to ieee80211_rx_napi, which may forward it in AP/mesh mode — a stack-disclosure primitive.
- I:HIntegrity impact, high
- In the !is_first_msdu branch, memcpy(decap_hdr, hdr, hdr_len) writes up to 6 attacker-chosen 802.11 header bytes past the 30-byte stack buffer, overwriting adjacent locals, the stack canary, or saved registers — a controlled OOB write and control-flow hijack primitive.
- A:HAvailability impact, high
- The smash is observed as "Kernel stack is corrupted in: ath11k_dp_rx_h_undecap" on the WBM path (ath11k_dp_rx_process_wbm_err → ath11k_dp_rx_h_mpdu). That trips __stack_chk_fail or FORTIFY_SOURCE, and skb_pull(hdr_len) on a short MSDU hits skb_under_panic.