CVE-2026-64254

What the bug is

When BAR_PEER_SPAD and BAR_CONFIG share one PCI BAR, the module teardown path ends up calling pci_iounmap() on the same iomem with some offset, which is unnecessary and triggers a kernel warning like the following: Trying to vunmap() nonexistent vm area (0000000069a5ffe8) WARNING: mm/vmalloc.c:3470 at vunmap+0x58/0x68, CPU#5: modprobe/2937 [...] Call trace: vunmap+0x58/0x68 (P) iounmap+0x34/0x48 pci_iounmap+0x2c/0x40 ntb_epf_pci_remove+0x44/0x80 [ntb_hw_epf] pci_device_remove+0x48/0xf8 device_remove+0x50/0x88 device_release_driver_internal+0x1c8/0x228 driver_detach+0x50/0xb0 bus_remove_driver+0x74/0x100 driver_unregister+0x34/0x68 pci_unregister_driver+0x34/0xa0 ntb_epf_pci_driver_exit+0x14/0xfe0 [ntb_hw_epf] [...] Fix it by unmapping only when PEER_SPAD and CONFIG use difference bars.

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/ntb/hw/epf/ntb_hw_epf.c

What this is

NTB DRIVER COREMAINTAINERS section matched on drivers/ntb/ · ntb@lists.linux.dev · Supported

Kernel module

none to look for. The file would have gone into ntb_hw_epf, and Debian does not compile it into that module, so finding ntb_hw_epf in lsmod would say nothing about this CVE.

Check it on the machine

grep -wE 'CONFIG_NTB|CONFIG_NTB_EPF' /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 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.

• bookworm, trixie, forky, sidn

n

not enabled on any flavour - this release does not build the code

Build switches

CONFIG_NTB, CONFIG_NTB_EPF

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

2026-07-24 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.11%, higher than 1.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/ntb

Upstream fixes

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

Introduced	Fixed in	Commit
6.0	6.1.177	eb47b9bffd07
6.0	6.6.144	06f6dd2ff2bd
6.0	6.12.95	a4be4a1308f0
6.0	6.18.38	81371dbd2360
6.0	7.1.3	9764a786ba98
6.0	7.2	d876153680e3

Debian advisories