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CVE-2026-93793
wifi: iwlwifi: mvm: validate TX_CMD response layout
Published 2026-09-24 (24 days ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-93793 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| 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
TX_CMD parsing uses frame_count to walk status entries and then read the trailing SCD SSN. Make the minimum-length check follow that exact runtime layout calculation before parsing the payload. For new TX API, reject TX_CMD responses with frame_count != 1 and warn/return in the aggregation handler to document that aggregated accounting is expected via BA notifications.
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/intel/iwlwifi/mvm/tx.c
- What this is
- INTEL WIRELESS WIFI LINK (iwlwifi)MAINTAINERS section matched on drivers/net/wireless/intel/iwlwifi/ · linux-wireless@vger.kernel.org · Supported
- Kernel module
- none to look for. The file would have gone into iwlmvm, and Debian does not compile it into that module, so finding iwlmvm in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_IWLMEI|CONFIG_IWLMVM|CONFIG_IWLWIFI|CONFIG_WLAN|CONFIG_WLAN_VENDOR_INTEL' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_IWLMEI, CONFIG_IWLMVM, CONFIG_IWLWIFI, CONFIG_WLAN, CONFIG_WLAN_VENDOR_INTEL
- 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
- 0.24%, higher than 13.9% 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 |
|---|---|---|
| 3.9 | 6.12.111 | fc14f5fe8a43 |
| 3.9 | 6.18.53 | 4d942dfc13ae |
| 3.9 | 7.2 | 8d70881707b4 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| 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 malformed input is a firmware TX_CMD (REPLY_TX 0x1c) notification DMA'd from the Intel WiFi NIC: iwl_pcie_rx_handle() → iwl_op_mode_rx() → iwl_mvm_rx()/iwl_mvm_rx_mq() → iwl_mvm_rx_common() → RX_HANDLER(TX_CMD, iwl_mvm_rx_tx_cmd). Those bytes are not a routable IP payload; WiFi host-device range is Adjacent.
- AC:LAttack complexity, low
- iwl_mvm_rx_tx_cmd() is RX_HANDLER_SYNC; a single TX_CMD whose firmware-chosen frame_count makes iwl_mvm_tx_resp_min_len() exceed iwl_rx_packet_payload_len() (or frame_count!=1 on the new TX API) is parsed immediately, with no race or victim state the sender cannot induce by posting that notification.
- PR:NPrivileges required, none
- iwl_mvm_rx_common() only checks pkt_len against sizeof(struct iwl_tx_resp) then calls iwl_mvm_rx_tx_cmd() with no uid, capability, or 802.11 authentication check; TX_CMD is in no_reclaim_cmds as a ucode-originated notif. An RF-adjacent attacker needs no host account.
- UI:NUser interaction, none
- The NAPI path consumes TX_CMD automatically when firmware posts a TX completion while the interface is up; iwl_mvm_rx_tx_cmd() does not require the victim to mount, open a file, or take any extra action at trigger time.
- S:UScope, unchanged
- iwl_mvm_get_scd_ssn() and iwl_trans_reclaim() from iwl_mvm_rx_tx_cmd_single() operate on host iwlwifi RX pages and TX queues inside the same kernel authority; this is not a KVM/Xen escape or an IOMMU/DMA-boundary bypass.
- C:HConfidentiality impact, high
- iwl_mvm_get_scd_ssn() does le32_to_cpup((__le32 *)agg_status + frame_count) with no payload check, and iwl_mvm_rx_tx_cmd_agg_dbg() walks status[frame_count] (u8, up to 255 entries). That is an out-of-bounds read past the TX_CMD into the RX page, and a poisoned SSN into iwl_trans_reclaim() is UAF-class.
- I:HIntegrity impact, high
- The over-read SCD SSN is passed to iwl_trans_reclaim()/iwl_pcie_reclaim(), which unmaps TFDs, NULLs txq->entries[].skb, and advances txq->read_ptr, completing in-flight TX buffers early. That is an out-of-bounds-fed free/write of live TX objects, not a bounded status update.
- A:HAvailability impact, high
- iwl_pcie_reclaim() WARNs on a missing skb or cmd-queue txq_id, and an SSN whose last_to_free is not in iwl_txq_used() desynchronizes the TX ring; walking status[frame_count] past the mapped RX buffer can oops. Kernel WARN/oops or a firmware-assert restart is high availability impact.