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CVE-2026-68404
wifi: cfg80211: use wiphy work for socket owner autodisconnect
Published 2026-08-10 (2 months ago) by the Linux kernel CNA. Subsystem include/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-68404 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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. |
The vulnerability
What the bug is
nl80211_netlink_notify() walks the cfg80211 wireless device list when a NETLINK_GENERIC socket is released. If the socket owns a connection, the notifier queues the embedded wdev->disconnect_wk work item. That work is a plain work_struct today. NETDEV_GOING_DOWN cancels it, but a NETLINK_URELEASE notifier that already observed conn_owner_nlportid can queue it after that cancel returns. _cfg80211_unregister_wdev() then removes the wdev from the list and waits for RCU readers, but synchronize_net() does not drain work queued by such a reader. Make the autodisconnect work a wiphy_work instead. The callback already needs the wiphy mutex, and wiphy_work runs under that mutex. This lets teardown cancel pending autodisconnect work while holding the mutex, without a cancel_work_sync() vs. worker locking concern. Also cancel the wiphy work after list_del_rcu() and synchronize_net(). Any NETLINK_URELEASE notifier that had already reached the wdev list has then either queued the work and it is removed, or can no longer find the wdev.
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.
include/net/cfg80211.h
net/wireless/core.c
net/wireless/core.h
net/wireless/nl80211.c
net/wireless/sme.c
- What this is
- 802.11 (including CFG80211/NL80211)MAINTAINERS section matched on include/net/cfg80211.h · linux-wireless@vger.kernel.org · Maintained
- Kernel module
- cfg80211
Check it on the machine
grep -wE 'CONFIG_CFG80211|CONFIG_WIRELESS' /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 cfg80211Prints 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
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_CFG80211, CONFIG_WIRELESS
- 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
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 4.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- include/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.11 | 6.18.57 | c2ddd180bbee |
| 4.11 | 7.1.6 | 6d6123fef5a4 |
| 4.11 | 7.2 | 0c2ed186bbe1 |
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:LAttack vector, local
- The vulnerability is reached through local nl80211/generic-netlink operations: setting NL80211_ATTR_SOCKET_OWNER on a connect/join command, closing the owning netlink socket, and tearing down the wireless interface. No network or radio traffic is required, so the attack vector is Local.
- AC:LAttack complexity, low
- The attacker controls both sides of the race — the NETLINK_URELEASE notification (by closing its own socket) and the wdev teardown (by downing/deleting the interface) — and can repeat the sequence in a tight loop until the work is queued after the cancel window.
- PR:LPrivileges required, low
- The relevant nl80211 commands use GENL_UNS_ADMIN_PERM and the family is netnsok, and mac80211_hwsim's HWSIM_CMD_NEW_RADIO likewise creates a wiphy in the caller's netns (wiphy_net_set(genl_info_net(info))), so an unprivileged user in a user+net namespace (unshare -Urn) obtains the required CAP_NET_ADMIN.
- UI:NUser interaction, none
- The entire sequence — creating/owning the connection, closing the socket, and removing the interface — is performed by the attacker's own process with no victim action required.
- S:UScope, unchanged
- The use-after-free corrupts kernel heap memory within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- The freed wireless_dev lives in the net_device private allocation; a use-after-free on that slab lets an attacker reclaim and inspect kernel heap contents, and cfg80211_autodisconnect_wk dereferences the stale object, enabling disclosure of arbitrary kernel memory.
- I:HIntegrity impact, high
- Queueing writes work list pointers into freed memory, and process_one_work() later loads work->func from the reclaimed allocation, giving an attacker who sprays the slab a controlled kernel function pointer call and thus arbitrary write/code execution.
- A:HAvailability impact, high
- Running cfg80211_autodisconnect_wk against a freed wireless_dev dereferences stale pointers and drives disconnect paths on destroyed state, reliably producing an oops or panic even without successful exploitation.