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CVE-2026-98311
wifi: virt_wifi: don't transfer operstate before register
Published 2026-10-06 (13 days 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-2026-98311 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-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.8-1 | Update the kernel and reboot. Fixed in 7.2.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.8-1 | Update the kernel and reboot. Fixed in 7.2.8-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
virt_wifi_newlink() calls netif_stacked_transfer_operstate() before register_netdevice(). If the lower device is dormant, that queues the new netdev on lweventlist while it is still uninitialized. If registration fails after that, for example because of an invalid name such as "bad/name", free_netdev() immediately frees the object. A later linkwatch_fire_event() then use-after-frees the list entry. Move the transfer to after netdev_upper_dev_link(), as macvlan and ipvlan already do.
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/virtual/virt_wifi.c
- What this is
- NETWORKING DRIVERS (WIRELESS)MAINTAINERS section matched on drivers/net/wireless/ · linux-wireless@vger.kernel.org · Maintained
Check it on the machine
grep -wE 'CONFIG_VIRT_WIFI|CONFIG_WLAN' /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 3 releases. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixie, forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_VIRT_WIFI, CONFIG_WLAN
- 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
- 2026-10-06 (13 days 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
- 0.14%, higher than 2.6% 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 |
|---|---|---|
| 5.0 | 5.10.271 | ee9ea1afd699 |
| 5.0 | 5.15.222 | 9ce26201f6de |
| 5.0 | 6.1.189 | f9526054c2b2 |
| 5.0 | 6.6.158 | e8304e25c6da |
| 5.0 | 6.12.112 | ca49763c42c1 |
| 5.0 | 6.18.54 | 293c56a66510 |
| 5.0 | 7.2.8 | b808a9af5fd2 |
| 5.0 | 7.3 | e5c8d7acd31b |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | 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:LAttack vector, local
- The trigger is a local RTM_NEWLINK netlink request of kind "virt_wifi" handled by virt_wifi_newlink(). No remote peer or WiFi frame supplies any input. The bug is a fault in the order of steps when creating the device.
- AC:LAttack complexity, low
- The attacker sets up the state and triggers it alone. They bring the lower device (e.g. lo) up and set it dormant via IFLA_OPERSTATE, then send RTM_NEWLINK with an invalid name like "bad/name". netif_dormant_on() queues the device on lweventlist, register_netdevice() fails and free_netdev() frees the device while it is still queued. No race is involved.
- PR:LPrivileges required, low
- rtnetlink_rcv_msg() and __rtnl_newlink() check CAP_NET_ADMIN only against the user namespace that owns the netns, so an unprivileged user can get it with unshare -Urn. __rtnl_newlink() also auto-loads rtnl-link-virt_wifi through request_module().
- UI:NUser interaction, none
- No victim action is needed; the attacker's own netlink messages create the dormant lower device, the failing virt_wifi link and the queued linkwatch event.
- S:UScope, unchanged
- Memory in the same kernel is corrupted and stays within the kernel's own security authority. No VM, IOMMU or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- The freed net_device is still linked into the global lweventlist. linkwatch_do_dev() later reads it (flags, state, qdisc pointers), so the attacker can reclaim the freed object with controlled data and use the resulting reads to leak memory.
- I:HIntegrity impact, high
- A list_add or list_del on lweventlist writes through link_watch_list into freed memory. With a reclaimed object, linkwatch_do_dev() calls dev_activate() or dev_deactivate() on qdisc pointers the attacker controls, which allows corrupting memory and hijacking control flow.
- A:HAvailability impact, high
- Even without careful exploitation, the queued linkwatch_event work or any later linkwatch_fire_event() corrupts list memory or touches freed memory. That causes a kernel oops or panic, and the attacker can repeat it.