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CVE-2026-64547
net: usb: net1080: validate packet_len before pad-byte access in rx_fixup
Published 2026-07-27 (3 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-2026-64547 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-4720-1 · 2026-08-05 · text | 6.1.180-1 | Update the kernel and reboot. DLA-4720-1 shipped the fix on 2026-08-05, in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6405-1 · 2026-07-31 · text | 6.12.100-1 | Update the kernel and reboot. DSA-6405-1 shipped the fix on 2026-07-31, 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
For an even packet_len, net1080_rx_fixup() reads the pad byte at skb->data[packet_len] before the skb->len != packet_len check further down, and packet_len is only bounded against NC_MAX_PACKET. A malicious NetChip 1080 device can send a short frame advertising a large even packet_len (e.g. 0x4000), so the pad-byte read lands past the end of the skb: BUG: KASAN: slab-out-of-bounds in net1080_rx_fixup Read of size 1 at addr ffff8880106c83c6 by task ksoftirqd/0/14 ... net1080_rx_fixup (drivers/net/usb/net1080.c:384) usbnet_bh (drivers/net/usb/usbnet.c:1589) process_one_work (kernel/workqueue.c:3322) bh_worker (kernel/workqueue.c:3708) tasklet_action (kernel/softirq.c:965) handle_softirqs (kernel/softirq.c:622) ... Reject the frame when packet_len >= skb->len before reading.
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/usb/net1080.c
- What this is
- USB NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/usb/ · linux-usb@vger.kernel.org · Odd Fixes
- Kernel module
- net1080
Check it on the machine
grep -wE 'CONFIG_USB_NET_DRIVERS|CONFIG_USB_NET_NET1080' /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 net1080Prints 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_USB_NET_DRIVERS, CONFIG_USB_NET_NET1080
- 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
- 2026-07-27 (3 months ago)source
- CVSS
- 8.1 high
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.27%, higher than 18.5% 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 |
|---|---|---|
| 2.6.14 | 5.10.261 | f42217fa7d53 |
| 2.6.14 | 5.15.212 | c08774981537 |
| 2.6.14 | 6.1.178 | e4a87126c085 |
| 2.6.14 | 6.6.145 | 685e92934f11 |
| 2.6.14 | 6.12.97 | 4dc8484be330 |
| 2.6.14 | 6.18.40 | b153cfe84b13 |
| 2.6.14 | 7.1.5 | ea866cab12db |
| 2.6.14 | 7.2 | 03f384bc0cb8 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4724-1 | 2026-08-07 | bookworm 6.12.100-1~deb12u1 | tracker |
| DLA-4723-1 | 2026-08-07 | bullseye 6.1.180-1~deb11u1 | tracker |
| DLA-4720-1 | 2026-08-05 | bookworm 6.1.180-1 | tracker |
| DLA-4717-1 | 2026-08-05 | bullseye 5.10.262-1 | tracker |
| DSA-6405-1 | 2026-07-31 | trixie 6.12.100-1 | 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
- net1080 implements a point-to-point Ethernet link over a USB host-to-host cable, so the malformed NC frame originates from the logically adjacent peer host/device on that link rather than from a local user; a compromised peer (or a gadget-mode board presenting 0525:1080, which autoloads the default-y driver) sends the frame over an already-established link with no physical interaction at attack time.
- AC:LAttack complexity, low
- The attacker fully and deterministically controls packet_len and the frame length in every received frame, so the out-of-bounds read is triggered on demand with no race, no timing dependency, and no reliance on memory layout the attacker cannot influence.
- PR:NPrivileges required, none
- The rx path runs in softirq/workqueue context on every received URB with no authentication, no capability check, and no local account on the target; USB/link-level peers are entirely untrusted and ungated.
- UI:NUser interaction, none
- The driver binds automatically via MODULE_DEVICE_TABLE and processes frames in usbnet_bh without any user action; on an already-connected host-to-host cable the victim does nothing at all.
- S:UScope, unchanged
- The out-of-bounds read stays within the kernel's own memory and security authority, with no crossing of a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- The attacker controls the read offset across a ~32 KB range past a 1523-byte slab/page-frag object, and the comparison outcome is leaked back over the wire because only the matching path reaches nc_ensure_sync()'s vendor control transfer, yielding a repeatable oracle for probing kernel heap contents rather than a bounded few-byte read.
- I:NIntegrity impact, none
- The path performs only a one-byte read; the subsequent skb->len != packet_len check still rejects the frame, and the skb_trim calls on the underflow paths are no-ops, so no kernel memory or network data is modified.
- A:HAvailability impact, high
- The read reaches roughly 31 KB beyond the allocation, which can cross into a KFENCE guard page, an unmapped hole, or a page-frag boundary and oops in softirq context, and on KASAN/panic_on_warn hardened kernels it panics the machine outright — repeatable per frame.