CVE-2026-72428

What the bug is

check_stack_write_fixed_off() computes the byte slot for a fixed-offset stack write as -off - 1, and records each written byte in slot_type[] with (slot - i) % BPF_REG_SIZE. The Spectre v4 sanitization pre-check uses slot_type[i] instead. For a 4-byte write at fp-8 after the lower half of fp-8 has been zeroed, the pre-check scans bytes 0..3 and sees STACK_ZERO while the actual write updates bytes 7..4. That can leave the second half-slot write without nospec_result even though the bytes being overwritten still require sanitization. Use the same slot index in the sanitization pre-check that the write path uses when updating slot_type[].

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.

kernel/bpf/verifier.c

What this is

BPF [CORE]MAINTAINERS section matched on kernel/bpf/verifier.c · bpf@vger.kernel.org · Maintained

Check it on the machine

grep -wE 'CONFIG_BPF|CONFIG_BPF_SYSCALL' /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 builds this code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sidy

y

built into the kernel image on every flavour - only a patch removes it

Build switches

CONFIG_BPF, CONFIG_BPF_SYSCALL

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

2026-08-15 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.22%, higher than 11.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

kernel/bpf

Upstream fixes

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

Introduced	Fixed in	Commit
5.10.56	5.10.261	e62268e69507
5.14	5.15.212	a71eb8f730a9
5.14	6.1.178	ca119656baa8
5.14	6.6.145	475405593de2
5.14	6.12.97	f1471aa76d74
5.14	6.18.40	68b41e68a622
5.14	7.1.5	db8f1dcf5950
5.14	7.2	d1d53aa30ab3
4.19.207	0	0
5.4.146	0	0
5.13.8	0	0