Look up another CVE · open CVE-2026-74341 in the interactive tracker
CVE-2026-74341
wifi: wcn36xx: fix heap overflow from oversized firmware HAL response
Published 2026-08-15 (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-2026-74341 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 dispatcher copies all synchronous HAL responses into the 4096-byte hal_buf without validating the response length. A response exceeding WCN36XX_HAL_BUF_SIZE causes a heap buffer overflow with firmware-controlled content. Add a bounds check on the response length.
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
- 2026-08-15 (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
- 0.52%, higher than 42.9% 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 |
|---|---|---|
| 3.13 | 6.1.178 | dae9cadf0925 |
| 3.13 | 6.6.145 | cfc67aee0c83 |
| 3.13 | 6.12.97 | 15545ee71301 |
| 3.13 | 6.18.40 | 1b5d8a248c3a |
| 3.13 | 7.1.5 | 18813b90032b |
| 3.13 | 7.2 | 88a240d86d3d |
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 wcn36xx_smd_rsp_process when copying synchronous HAL replies from WCN3660/3680 firmware over WLAN_CTRL rpmsg; crafted 802.11 traffic can cause the firmware to return oversized responses during normal scan/association on nearby Qualcomm Android devices.
- AC:LAttack complexity, low
- The driver copies the full rpmsg length into a 4096-byte hal_buf with no validation; an adjacent attacker can repeatedly send malicious WiFi frames during background scanning to reliably elicit an oversized synchronous HAL response while the host awaits completion.
- PR:NPrivileges required, none
- No local account or kernel privileges are required on the victim; exploitation only needs radio proximity to a device running the wcn36xx driver with WiFi active, a typical scenario for phones and tablets in public spaces.
- UI:NUser interaction, none
- No specific victim interaction is required beyond routine WiFi operation; devices continuously scan and associate automatically, allowing an adjacent attacker to deliver malicious frames passively or via a rogue access point.
- S:UScope, unchanged
- Heap corruption occurs in the wcn36xx kernel driver during firmware response handling, enabling standard kernel privilege escalation rather than crossing a VM, IOMMU, or other separate security authority boundary.
- C:HConfidentiality impact, high
- The unchecked memcpy writes firmware-controlled bytes past the 4096-byte hal_buf kmalloc allocation, corrupting adjacent heap objects and providing primitives for arbitrary kernel memory disclosure during exploitation.
- I:HIntegrity impact, high
- This is a heap buffer overflow with attacker-controlled overflow content that can overwrite adjacent kernel heap metadata and objects, enabling control-flow hijacking and arbitrary kernel code execution.
- A:HAvailability impact, high
- Synchronous heap corruption in the rpmsg receive path can immediately cause kernel oops or panic during the memcpy or subsequent allocator use, resulting in complete loss of system and wireless availability.