CVE-2026-74566

What the bug is

keyring_get_key_chunk() loads description bytes into the index chunk low address first, while keyring_diff_objects() numbers the first differing bit from the low end and folds the absolute byte index into the level without removing the inline-prefix offset the level already carries. The two disagree on byte order and bit position, so the array can be told two keys first differ at a bit that does not differ in the chunk the walker uses, letting crafted descriptions collide into one node. Load the chunk in the order keyring_diff_objects() assumes and drop the inline-prefix length when folding the byte index into the level. This only changes the in-memory ordering used to place keys within a keyring; add, search and read of non-colliding keys are unaffected.

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.

security/keys/keyring.c

What this is

KEYS/KEYRINGSMAINTAINERS section matched on security/keys/ · keyrings@vger.kernel.org · Maintained

Check it on the machine

grep -w CONFIG_KEYS /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, sid, bookworm · linux-6.12y

y

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

Build switch

CONFIG_KEYS

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

0.17%, higher than 5.3% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

security/keys

Upstream fixes

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

Introduced	Fixed in	Commit
5.3	5.10.265	414bcf37d81c
5.3	5.15.216	abe43c661efb
5.3	6.1.183	f81920917074
5.3	6.6.151	bd0f976ef89d
5.3	6.12.103	7269df3e7fcf
5.3	6.18.44	3d9f16c0b643
5.3	7.1.8	7e5397a3fed0
5.3	7.2	58565eef0f8d

Debian advisories