Look up another CVE · open CVE-2026-64585 in the interactive tracker

CVE-2026-64585

can: esd_usb: kill anchored URBs before freeing netdevs

7.8 EPSS 0.1% AV:L

Published 2026-08-06 (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-2026-64585 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.
Debian 12bookworm · linux-6.12	fixedDLA-4724-1 · 2026-08-07 · text	6.12.100-1~deb12u1	Update the kernel and reboot. DLA-4724-1 shipped the fix on 2026-08-07, in 6.12.100-1~deb12u1. A running kernel keeps the old code until the machine restarts.

The vulnerability

What the bug is

esd_usb_disconnect() frees each CAN netdev with free_candev() inside its per-netdev loop and only calls unlink_all_urbs(dev) afterwards. The per-netdev private data (struct esd_usb_net_priv) is embedded in the net_device allocation returned by alloc_candev(), so once free_candev() has run, dev->nets[i] points to freed memory. unlink_all_urbs() then dereferences the freed dev->nets[i] to kill the per-netdev TX anchor (usb_kill_anchored_urbs(&priv->tx_submitted)), clear active_tx_jobs, and reset priv->tx_contexts[]. Reorder the teardown so the anchored URBs are killed before the netdevs are freed, matching other CAN/USB drivers in the same directory such as ems_usb, usb_8dev and mcba_usb, which unregister, then unlink, then free: unregister the netdevs first (which stops their TX queues), call unlink_all_urbs(dev) once, then free the netdevs. This issue was found by an in-house static analysis tool.

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/can/usb/esd_usb.c

What this is: ESD CAN/USB DRIVERSMAINTAINERS section matched on drivers/net/can/usb/esd_usb.c · linux-can@vger.kernel.org · Maintained
Kernel module: esd_usb

Check it on the machine

grep -wE 'CONFIG_CAN|CONFIG_CAN_ESD_USB' /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 esd_usb

Prints 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.

bookworm, trixie, forky, sid, 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_CAN, CONFIG_CAN_ESD_USB
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

Debian tracker CVE record NVD kernel CNA record

Signals

Published: 2026-08-06 (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: 0.12%, higher than 1.7% 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
2.6.36	5.15.217	d12f6add48f2
2.6.36	6.1.178	aa1d005927db
2.6.36	6.6.145	a02e1d8f1913
2.6.36	6.12.97	a3314f10369d
2.6.36	6.18.40	765ba1c91823
2.6.36	7.1.5	5832c55b3c82
2.6.36	7.2	c43122fef328

Debian advisories

Advisory	Date	Shipped to	Debian
DLA-4724-1	2026-08-07	bookworm 6.12.100-1~deb12u1	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 UAF is reached by forcing esd_usb_disconnect() via local usbfs USBDEVFS_DISCONNECT, sysfs unbind, or USB emulation, not by network/CAN traffic; this matches AV:L scoring of analogous USB disconnect UAFs (e.g. CVE-2025-40283).
AC:LAttack complexity, low: Once disconnect runs, free_candev() then unlink_all_urbs() deterministically uses freed esd_usb_net_priv in the same teardown path; the attacker fully controls when unbind occurs, with no attacker-uncontrollable race required.
PR:LPrivileges required, low: A basic local account with write access to the USB device node (plugdev/uaccess or USB passthrough) can issue USBDEVFS_DISCONNECT; that path has no CAP_SYS_ADMIN check, so init-namespace root is not required.
UI:NUser interaction, none: The attacker issues disconnect/unbind against an already-bound esd CAN-USB interface (or their own matching VID/PID device) without any separate victim action.
S:UScope, unchanged: The freed netdev-private object and subsequent URB teardown run entirely within the host kernel security authority; this is not a VM, IOMMU, or sandbox boundary escape.
C:HConfidentiality impact, high: Use-after-free of struct esd_usb_net_priv (embedded in the freed candev) lets a reclaimed object supply attacker-controlled pointer-rich state read through usb_kill_anchored_urbs() and related teardown, enabling kernel disclosure.
I:HIntegrity impact, high: unlink_all_urbs() writes through the freed priv (usb_kill_anchored_urbs on tx_submitted, atomic_set of active_tx_jobs, and tx_contexts[] resets), giving a heap UAF write primitive suitable for control-flow hijack.
A:HAvailability impact, high: Dereferencing the freed per-netdev private data during disconnect reliably causes kernel oops/panic, and the attacker can repeat unbind/rebind to re-trigger the crash.