CVE-2026-98612

What the bug is

catc_rx_done() walks a multi-packet URB, reading a two-byte length from each packet header. Its bound, pkt_len > urb->actual_length, ignores the header offset and compares against the whole transfer rather than the bytes left from pkt_start, so a crafted packet header makes skb_copy_to_linear_data() read past the buffer. A length below ETH_HLEN is also accepted, including zero, and eth_type_trans() then reads a MAC header from the uninitialised tailroom of a shorter skb. The is_f5u011 branch takes its length straight from the transfer, so a zero-length URB reaches the same path. Track the bytes remaining from the current packet, and reject a header that does not fit, a length past what is left, and a length below an Ethernet header. A transfer shorter than an Ethernet header, including a zero-length one, previously became a runt skb passed to netif_rx() and counted as received; it is now counted in rx_length_errors and ends the walk.

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/catc.c

What this is

USB NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/usb/ · linux-usb@vger.kernel.org · Odd Fixes

Kernel module

catc

Check it on the machine

grep -wE 'CONFIG_USB_CATC|CONFIG_USB_NET_DRIVERS' /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 catc

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, sidMnot 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_CATC, CONFIG_USB_NET_DRIVERS

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

2026-10-18 (today)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

not scored

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
2.6.12	5.10.271	3942557938f8
2.6.12	5.15.222	2f87bbd5a7bf
2.6.12	6.1.189	4cc0a8eb2f93
2.6.12	6.6.158	21e206dd88b3
2.6.12	6.12.112	801e21cf7dd6
2.6.12	6.18.55	dd9c6f8f0517
2.6.12	7.2.9	9d4be026bdff
2.6.12	7.3	9d565b6b72fe