CVE-2026-93261

What the bug is

register_lock_class() can return NULL when the lock class pool is exhausted, graph_lock() fails, or key validation fails. However, __lock_set_class() uses the return value directly in pointer arithmetic without a NULL check: class = register_lock_class(lock, subclass, 0); hlock->class_idx = class - lock_classes; If class is NULL, this computes a wild offset that corrupts hlock->class_idx. The subsequent reacquire_held_locks() call will invoke hlock_class() with this corrupted index, leading to a NULL or out-of-bounds pointer dereference. Add the missing NULL check, consistent with how __lock_acquire() already handles this case at the same call site.

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/locking/lockdep.c

What this is

LOCKING PRIMITIVESMAINTAINERS section matched on kernel/locking/ · linux-kernel@vger.kernel.org · Maintained

Kernel module

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

Check it on the machine

grep -w CONFIG_LOCKDEP /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 5 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, sid, bookworm · linux-6.12n

n

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

Build switch

CONFIG_LOCKDEP

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

2026-09-24 (24 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.20%, higher than 8.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

kernel/locking

Upstream fixes

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

Introduced	Fixed in	Commit
2.6.27	5.10.270	f6093ff67ea6
2.6.27	5.15.221	59a5c7dd331a
2.6.27	6.1.188	f56e54fd24f0
2.6.27	6.6.157	5c3bff6cf26e
2.6.27	6.12.110	b2113dcd8238
2.6.27	6.18.52	e7c69c6695d8
2.6.27	7.2.6	9be10f49dfc2
2.6.27	7.3	7577e00b9ab5

Debian advisories