Look up another CVE · open CVE-2026-80635 in the interactive tracker
CVE-2026-80635
wifi: wcn36xx: fix OOB read from short trigger BA firmware response
Published 2026-08-28 (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-2026-80635 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The firmware response length is only checked against sizeof(*rsp) (20 bytes), but when candidate_cnt >= 1, a 22-byte candidate struct is read at buf + 20 without verifying the response contains it. This causes an out-of-bounds read of stale heap data, corrupting the BA session state. Add validation that the response includes the candidate data.
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/wcn36xx/smd.c
- What this is
- QUALCOMM WCN36XX WIRELESS DRIVERMAINTAINERS section matched on drivers/net/wireless/ath/wcn36xx/ · wcn36xx@lists.infradead.org · Supported
- Kernel module
- wcn36xx
Check it on the machine
grep -wE 'CONFIG_WCN36XX|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 wcn36xxPrints 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/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_WCN36XX, 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
- 2026-08-28 (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
- 0.40%, higher than 33.0% 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 |
|---|---|---|
| 4.7 | 6.1.178 | 04aba50212f9 |
| 4.7 | 6.6.145 | c07aa0534d50 |
| 4.7 | 6.12.97 | d0b57bcd0dac |
| 4.7 | 6.18.40 | af8f0ea1f0a3 |
| 4.7 | 7.1.5 | d0cafe6ed8d1 |
| 4.7 | 7.2 | b5e6f21923ca |
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 parsing a WLAN firmware HAL response during TX block-ack setup; that path is reached only when an adjacent 802.11 peer drives AMPDU/BA negotiation over WiFi, not via remote IP or local syscalls.
- AC:LAttack complexity, low
- An adjacent attacker can repeatedly send QoS data to a victim using wcn36xx to force ieee80211_start_tx_ba_session and wcn36xx_smd_trigger_ba, retrying until firmware returns a short TRIGGER_BA_RSP with candidate_cnt>=1.
- PR:NPrivileges required, none
- Exploitation requires only wireless adjacency as an associated AP or client peer; no Linux account, capabilities, or user-namespace privileges on the victim host are needed.
- UI:NUser interaction, none
- The victim needs no deliberate action beyond normal WiFi use; the attacker triggers BA setup by sending traffic that causes automatic AMPDU aggregation on the victim interface.
- S:UScope, unchanged
- Impact is confined to the kernel WiFi driver and its firmware session state on the same host; it does not cross VM, container, or IOMMU security boundaries.
- C:HConfidentiality impact, high
- When candidate_cnt>=1 but the response is only 20 bytes, the driver OOB-reads a 22-byte candidate from stale hal_buf data beyond the message, disclosing adjacent kernel buffer contents that may include prior HAL keying material.
- I:HIntegrity impact, high
- Stale OOB data is copied into ba_info and used as the block-ack starting sequence number for wcn36xx_smd_add_ba_session, corrupting BA session state and subsequent driver/firmware behavior.
- A:HAvailability impact, high
- Corrupted block-ack parameters and malformed firmware/driver state can destabilize the WLAN subsystem, causing connection loss, firmware/driver errors, or kernel crashes under repeated attack.