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CVE-2026-68199
wifi: ath6kl: fix OOB access from firmware ADDBA window size
Published 2026-08-10 (2 months 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-2026-68199 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-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
aggr_recv_addba_req_evt() logs a debug message when the firmware-supplied win_sz is outside [AGGR_WIN_SZ_MIN, AGGR_WIN_SZ_MAX] but does not return. The out-of-range win_sz is then used in TID_WINDOW_SZ() to compute a kzalloc size and stored in rxtid->hold_q_sz, leading to zero-size or overflowed allocations and subsequent out-of-bounds access. Clean up any previously active aggregation session for the TID first, then return early when win_sz is out of the valid range, instead of proceeding with a broken allocation size.
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/ath6kl/txrx.c
- What this is
- ATHEROS ATH6KL WIRELESS DRIVERMAINTAINERS section matched on drivers/net/wireless/ath/ath6kl/ · linux-wireless@vger.kernel.org · Orphan
- Kernel module
- ath6kl_core
Check it on the machine
grep -wE 'CONFIG_ATH6KL|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 ath6kl_corePrints 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_ATH6KL, 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
- 2026-08-10 (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
- 0.41%, higher than 33.4% 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 |
|---|---|---|
| 3.2 | 5.10.265 | c8e3ca7954d8 |
| 3.2 | 5.15.216 | f480d9910fcf |
| 3.2 | 6.1.183 | 67bc9af4f41f |
| 3.2 | 6.6.148 | d4558c140782 |
| 3.2 | 6.12.101 | 5a65fd472241 |
| 3.2 | 6.18.42 | 58c6c8dc2e02 |
| 3.2 | 7.1.6 | cec0a487cf38 |
| 3.2 | 7.2 | 44126b6994ee |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | 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
- Exploitation requires a malicious WiFi peer (rogue AP or associated client) to trigger ADDBA handling; firmware passes WMI_ADDBA_REQ_EVENTID over the radio link to the ath6kl driver, placing the attacker on the same wireless segment rather than a remote IP network path.
- AC:LAttack complexity, low
- An adjacent attacker can reliably send crafted 802.11 ADDBA requests with out-of-range buffer/window sizes to firmware, which forwards the invalid win_sz to the host; no special memory layout, race, or rare timing is required beyond normal WiFi association.
- PR:NPrivileges required, none
- No local Linux privileges are needed; any associated WiFi peer can induce the malformed ADDBA event. The bug is not reachable via user namespaces or unprivileged local syscalls without controlling the WiFi link/firmware messages.
- UI:NUser interaction, none
- Once the victim device is associated to WiFi (common on phones, embedded, and IoT), the attacker can send ADDBA and follow-up data frames without any additional victim action beyond routine wireless connectivity.
- S:UScope, unchanged
- Heap corruption and kernel privilege escalation occur within the same kernel security domain; this is not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.
- C:HConfidentiality impact, high
- Out-of-bounds access to hold_q allows reading/writing adjacent kernel heap memory (e.g., skb pointers and metadata); OOB kernel heap access is treated as arbitrary memory disclosure potential per kernel CVSS guidance.
- I:HIntegrity impact, high
- OOB writes to hold_q entries (struct sk_buff pointers, is_amsdu, seq_no) corrupt kernel heap state and can be leveraged for control-flow hijacking and local privilege escalation, not merely a bounded modification.
- A:HAvailability impact, high
- Invalid win_sz can yield zero-size allocations and hold_q_sz=0 (divide-by-zero in AGGR_WIN_IDX) or inconsistent buffers, causing kernel oops/panic or persistent disruption when aggregation receives subsequent frames.