Look up another CVE · open CVE-2026-74488 in the interactive tracker
CVE-2026-74488
wifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames
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-2026-74488 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 | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
mwifiex_11n_dispatch_amsdu_pkt() splits an A-MSDU with ieee80211_amsdu_to_8023s() and walks the resulting subframes. For each subframe it passes the subframe data pointer to mwifiex_process_tdls_action_frame(), but pairs it with skb->len, the length of the A-MSDU parent, instead of rx_skb->len: rx_skb = __skb_dequeue(&list); rx_hdr = (struct rx_packet_hdr *)rx_skb->data; if (ISSUPP_TDLS_ENABLED(priv->adapter->fw_cap_info) && ntohs(rx_hdr->eth803_hdr.h_proto) == ETH_P_TDLS) { mwifiex_process_tdls_action_frame(priv, (u8 *)rx_hdr, skb->len); } The parent is not a valid description of that buffer, and may not be valid memory at all. ieee80211_amsdu_to_8023s() ends with if (!reuse_skb) dev_kfree_skb(skb); and it only sets reuse_skb when the parent is linear, is not a head_frag, and is being consumed as the *last* subframe. So when the parent does not qualify for reuse it has already been freed, and the read of skb->len is a use-after-free. When it is reused, skb->len is the length of the last subframe, applied to every earlier subframe, which over-states the buffer whenever an earlier subframe is shorter. The callee cannot absorb a wrong length, because it derives its own ceiling from the value it is given. Each frame type computes ies_len = len - sizeof(struct ethhdr) - TDLS_*_FIX_LEN; and the element walk is then bounded entirely against that ceiling, for (end = pos + ies_len; pos + 1 < end; pos += 2 + pos[1]) { u8 ie_len = pos[1]; if (pos + 2 + ie_len > end) break; so a too-large len moves end past the end of the subframe and the walk reads and copies beyond it. The A-MSDU layout is chosen by the sender, which makes the difference between the last subframe and a shorter earlier one remotely selectable. Reaching this requires TDLS support in firmware and the TDLS ethertype on the subframe. The other caller, mwifiex_process_rx_packet(), is correct: it passes a pointer and a length that describe the same region of the RX buffer. Pass rx_skb->len, the length of the subframe actually being parsed.
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/marvell/mwifiex/11n_rxreorder.c
- What this is
- MARVELL MWIFIEX WIRELESS DRIVERMAINTAINERS section matched on drivers/net/wireless/marvell/mwifiex/ · linux-wireless@vger.kernel.org · Odd Fixes
- Kernel module
- mwifiex
Check it on the machine
grep -wE 'CONFIG_MWIFIEX|CONFIG_WLAN|CONFIG_WLAN_VENDOR_MARVELL' /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 mwifiexPrints 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, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, loong64/loong64, riscv64/riscv64, 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_MWIFIEX, CONFIG_WLAN, CONFIG_WLAN_VENDOR_MARVELL
- 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
- 0.26%, higher than 15.9% 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 |
|---|---|---|
| 4.5 | 5.10.265 | 707664027bb9 |
| 4.5 | 5.15.216 | 3b02275833a0 |
| 4.5 | 6.1.183 | a1f0f7dc7eb1 |
| 4.5 | 6.6.151 | 25e5a3fe4f15 |
| 4.5 | 6.12.103 | ece2ebb34247 |
| 4.5 | 6.18.44 | c9dcfe6b8b71 |
| 4.5 | 7.1.8 | 5a21ab03829c |
| 4.5 | 7.2 | 99a948382af8 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | 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 bug is reached when the mwifiex driver processes attacker-supplied A-MSDU TDLS frames received over WiFi from a nearby peer, AP, or injector on the same wireless segment, which is an adjacent RF attack vector rather than remote Internet or local syscall access.
- AC:LAttack complexity, low
- Once TDLS-capable mwifiex firmware receives an A-MSDU, the attacker fully controls subframe sizes and TDLS content to trigger either the skb use-after-free or the overstated-length out-of-bounds parse reliably without depending on uncontrollable timing or memory layout.
- PR:NPrivileges required, none
- Exploitation requires only the ability to deliver crafted 802.11 data frames to the victim radio; it does not require any local account, capability, or root access on the Linux host and is not gated by user-namespace privilege boundaries.
- UI:NUser interaction, none
- No victim user action beyond normal wireless operation is required; the driver parses malicious TDLS subframes automatically during receive and A-MSDU decomposition before forwarding traffic to the network stack.
- S:UScope, unchanged
- Impact is confined to kernel memory corruption and driver state within the host kernel security authority; it does not by itself cross a VM, container, or IOMMU boundary to affect a separate security domain.
- C:HConfidentiality impact, high
- The skb use-after-free reads freed sk_buff metadata and the inflated length drives an out-of-bounds IE walk that reads kernel memory beyond the subframe, including attacker-positioned bytes from subsequent A-MSDU subframes, enabling substantial information disclosure.
- I:HIntegrity impact, high
- The same out-of-bounds parse copies attacker-controlled IE data from beyond the subframe into heap-allocated sta_node/tdls_cap structures via memcpy, providing a memory-corruption primitive that can be developed into arbitrary kernel write or code execution.
- A:HAvailability impact, high
- Reading skb->len after the parent A-MSDU skb may already be freed can immediately fault or corrupt memory, and the out-of-bounds TDLS element parsing can provoke kernel oopses or panics even when full exploitation is not attempted.