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NVD / CVE Program· CNA Linux

CVE-2026-90190: null_blk: use DEFINE_MUTEX for the file-scope mutex

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 017dac7670909eaea3eb36e6b3b5a8be9ce0a14d, 0a8c2f7b95981913ac370683e34db4906970c210, 234117949da3b3f9705a21b66094f9f30bbe681d.

Low priority for now. Upgrade to Linux Linux 017dac7670909eaea3eb36e6b3b5a8be9ce0a14d, 0a8c2f7b95981913ac370683e34db4906970c210, 234117949da3b3f9705a21b66094f9f30bbe681d or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.19affected
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before f9f4ca45c770b7eec83fea6c9b727b26e691b513affected · git
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before 349903f7ee72f7ac5b7a98840d701b2082d140a3affected · git
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before 0a8c2f7b95981913ac370683e34db4906970c210affected · git
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33caffected · git
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before 234117949da3b3f9705a21b66094f9f30bbe681daffected · git
    • 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b and later · before 017dac7670909eaea3eb36e6b3b5a8be9ce0a14daffected · git
    • before 5.19not affected · semver
    • 6.1.188 and later · up to and including 6.1.*not affected · semver
    • 6.6.157 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90188Sep 17, 2026 · null_blk: free global tag_set on init error path
    0Monitor
  • ← EarlierCVE-2026-90189Sep 17, 2026 · null_blk: register configfs subsystem after creating default devices
    0Monitor
  • Later →CVE-2026-90191Sep 17, 2026 · mailbox: riscv-sbi-mpxy: validate RPMI notification lengths
    33Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux017dac7670909eaea3eb36e6b3b5a8be9ce0a14dVendor (CNA)
Linux Linux0a8c2f7b95981913ac370683e34db4906970c210Vendor (CNA)
Linux Linux234117949da3b3f9705a21b66094f9f30bbe681dVendor (CNA)
Linux Linux349903f7ee72f7ac5b7a98840d701b2082d140a3Vendor (CNA)
Linux Linuxc7dea90c9b4ef1dfbd2e4df36de180c76fd7c33cVendor (CNA)
Linux Linuxf9f4ca45c770b7eec83fea6c9b727b26e691b513Vendor (CNA)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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