CVE-2026-90190 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-DEBIAN12-LINUX612-20507217
- published5 Oct 2026
- disclosed17 Sept 2026
Introduced: 17 Sep 2026
NewCVE-2026-90190 (opens in a new tab)How to fix?
Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
null_blk: use DEFINE_MUTEX for the file-scope mutex
In null_init(), mutex_init(&lock) currently happens after configfs_register_subsystem(), which exposes the nullb subsystem to userspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach null_find_dev_by_name() -> mutex_lock(&lock) before the mutex is initialized, trigger warning:
[ 123.137788] DEBUG_LOCKS_WARN_ON(lock->magic != lock) [ 123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301 [ 123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 ...... [ 123.154926] Call Trace: [ 123.155172] <TASK> [ 123.155419] ? __pfx_mutex_lock+0x10/0x10 [ 123.156181] ? __pfx__raw_spin_lock+0x10/0x10 [ 123.156571] nullb_group_make_group+0x20/0x100 [null_blk] [ 123.157011] configfs_mkdir+0x47b/0xc70 [ 123.157337] ? __pfx_configfs_mkdir+0x10/0x10 [ 123.157719] ? may_create_dentry+0x242/0x2e0 [ 123.158061] vfs_mkdir+0x2a9/0x6c0 [ 123.158352] filename_mkdirat+0x3dc/0x500 [ 123.158710] ? __pfx_filename_mkdirat+0x10/0x10 [ 123.159070] ? strncpy_from_user+0x3a/0x1d0 [ 123.159413] __x64_sys_mkdir+0x6b/0x90 [ 123.159760] do_syscall_64+0xea/0x600
Replace the runtime mutex_init(&lock) with a static DEFINE_MUTEX(lock) declaration to fix this issue.
References
- https://security-tracker.debian.org/tracker/CVE-2026-90190
- https://git.kernel.org/stable/c/017dac7670909eaea3eb36e6b3b5a8be9ce0a14d
- https://git.kernel.org/stable/c/0a8c2f7b95981913ac370683e34db4906970c210
- https://git.kernel.org/stable/c/234117949da3b3f9705a21b66094f9f30bbe681d
- https://git.kernel.org/stable/c/349903f7ee72f7ac5b7a98840d701b2082d140a3
- https://git.kernel.org/stable/c/c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c
- https://git.kernel.org/stable/c/f9f4ca45c770b7eec83fea6c9b727b26e691b513