CVE-2026-63890

What the bug is

drivers/scsi/fcoe/fcoe_ctlr.c::fcoe_ctlr_recv_clr_vlink() advanced the descriptor cursor by an attacker-supplied fip_dlen without ever requiring dlen >= sizeof(struct fip_desc) in the default branch. The named descriptor cases (FIP_DT_MAC, FIP_DT_NAME, FIP_DT_VN_ID) checked their per-type minimum lengths, but a FIP_DT_NON_CRITICAL descriptor (fip_dtype >= 128, which the standard requires receivers to silently ignore) skipped that check entirely. An unauthenticated L2 peer on the FCoE control VLAN could hang fcoe_ctlr_recv_work on an fcoe, qedf, or bnx2fc initiator indefinitely by emitting one FIP CVL frame whose single descriptor had fip_dtype == FIP_DT_NON_CRITICAL and fip_dlen == 0: the cursor advanced zero bytes per iteration and the loop condition rlen >= sizeof(*desc) stayed true forever, blocking every subsequent FIP frame on that controller. Tighten the outer dlen guard to also reject dlen < sizeof(struct fip_desc), so a malformed descriptor whose length cannot even cover the descriptor header is rejected before the switch. This is the same lower-bound the named cases already apply and is the minimum scope that closes the loop.

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/scsi/fcoe/fcoe_ctlr.c

What this is

FCOE SUBSYSTEM (libfc, libfcoe, fcoe)MAINTAINERS section matched on drivers/scsi/fcoe/ · linux-scsi@vger.kernel.org · Supported

Kernel module

libfcoe

Check it on the machine

grep -wE 'CONFIG_FCOE|CONFIG_LIBFCOE|CONFIG_SCSI_BNX2X_FCOE' /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 libfcoe

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.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi
• 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_FCOE, CONFIG_LIBFCOE, CONFIG_SCSI_BNX2X_FCOE

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

2026-07-19 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.23%, higher than 12.3% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/scsi

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
2.6.30	5.10.259	d179949d2175
2.6.30	5.15.210	fda976f7390b
2.6.30	6.1.176	80a0cd307205
2.6.30	6.6.143	0e3c6e5a8fc1
2.6.30	6.12.93	549859a11310
2.6.30	6.18.35	14dd80a20a72
2.6.30	7.0.12	d537d29d51c8
2.6.30	7.1	9eed1bd59937