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NVD / CVE Program· CNA Linux

CVE-2026-43271: md-cluster: fix NULL pointer dereference in process_metadata_update

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 721599e837d3f4c0e6cc14da059612c017b6d3ec, a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1, dceb5a843910004cb118148e267036104fc3ee43.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 721599e837d3f4c0e6cc14da059612c017b6d3ec, a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1, dceb5a843910004cb118148e267036104fc3ee43 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: md-cluster: fix NULL pointer dereference in process_metadata_update The function process_metadata_update() blindly dereferences the 'thread' pointer (acquired via rcu_dereference_protected) within the wait_event() macro. While the code comment states "daemon thread must exist", there is a valid race condition window during the MD array startup sequence (md_run): 1. bitmap_load() is called, which invokes md_cluster_ops->join(). 2. join() starts the "cluster_recv" thread (recv_daemon). 3. At this point, recv_daemon is active and processing messages. 4. However, mddev->thread (the main MD thread) is not initialized until later in md_run(). If a METADATA_UPDATED message is received from a remote node during this specific window, process_metadata_update() will be called while mddev->thread is still NULL, leading to a kernel panic. To fix this, we must validate the 'thread' pointer. If it is NULL, we release the held lock (no_new_dev_lockres) and return early, safely ignoring the update request as the array is not yet fully ready to process it.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 6, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.12 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.16
  • linux linux kernel6.19 and later · before 6.19.6

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

    • 4.12affected
    • 0ba959774e93911caff596de6391f085fb640ac4 and later · before a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1affected · git
    • 0ba959774e93911caff596de6391f085fb640ac4 and later · before dec123825c1ed74d98fd5fc7571a851dea4f46ffaffected · git
    • 0ba959774e93911caff596de6391f085fb640ac4 and later · before 721599e837d3f4c0e6cc14da059612c017b6d3ecaffected · git
    • 0ba959774e93911caff596de6391f085fb640ac4 and later · before dceb5a843910004cb118148e267036104fc3ee43affected · git
    • 0ba959774e93911caff596de6391f085fb640ac4 and later · before f150e753cb8dd756085f46e86f2c35ce472e0a3caffected · git
    • before 4.12not affected · semver
    • 6.6.128 and later · up to and including 6.6.*not affected · semver
    • 6.12.75 and later · up to and including 6.12.*not affected · semver
    • 6.18.16 and later · up to and including 6.18.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.6-16.19.6-1
openSUSE:Leap 16.0dtb-aarch64before 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-64kbbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-azurebefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-defaultbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-default-basebefore 6.12.0-160000.38.1.160000.2.226.12.0-160000.38.1.160000.2.22
openSUSE:Leap 16.0kernel-docsbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-kvmsmallbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-obs-buildbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-obs-qabefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-rtbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-sourcebefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-symsbefore 6.12.0-160000.38.16.12.0-160000.38.1
openSUSE:Leap 16.0kernel-zfcpdumpbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Server 16.0kernel-azurebefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Server 16.0kernel-docsbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Server 16.0kernel-kvmsmallbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Server 16.0kernel-obs-qabefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Enterprise Server 16.0kernel-zfcpdumpbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Micro 6.2kernel-64kbbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Micro 6.2kernel-defaultbefore 6.12.0-160000.38.16.12.0-160000.38.1
SUSE:Linux Micro 6.2kernel-default-basebefore 6.12.0-160000.38.1.160000.2.236.12.0-160000.38.1.160000.2.23

+4

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-43269May 6, 2026 · drm/atmel-hlcdc: fix memory leak from the atomic_destroy_state callback
    22Monitor
  • ← EarlierCVE-2026-43270May 6, 2026 · media: mtk-mdp: Fix a reference leak bug in mtk_mdp_remove()
    22Monitor
  • Later →CVE-2026-43273May 6, 2026 · ceph: supply snapshot context in ceph_zero_partial_object()
    22Monitor

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 Linux721599e837d3f4c0e6cc14da059612c017b6d3ecVendor (CNA)
Linux Linuxa61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1Vendor (CNA)
Linux Linuxdceb5a843910004cb118148e267036104fc3ee43Vendor (CNA)
Linux Linuxdec123825c1ed74d98fd5fc7571a851dea4f46ffVendor (CNA)
Linux Linuxf150e753cb8dd756085f46e86f2c35ce472e0a3cVendor (CNA)
debian:linux6.12.85-1 · Debian:13Package registry (OSV)
opensuse:dtb-aarch646.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-64kb6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-azure6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default-base6.12.0-160000.38.1.160000.2.22 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-docs6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-kvmsmall6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-build6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-qa6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-rt6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-source6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-syms6.12.0-160000.38.1 · openSUSE:Leap 16.0Package registry (OSV)
suse:kernel-64kb6.12.0-160000.38.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-azure6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-default6.12.0-160000.38.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-default-base6.12.0-160000.38.1.160000.2.23 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-docs6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-kvmsmall6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-obs-build6.12.0-160000.38.1 · SUSE:Linux Micro Extras 6.2Package registry (OSV)
suse:kernel-obs-qa6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:kernel-rt6.12.0-160000.38.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-source6.12.0-160000.38.1 · SUSE:Linux Micro 6.2Package registry (OSV)
suse:kernel-syms6.12.0-160000.38.1 · SUSE:Linux Micro Extras 6.2Package registry (OSV)
suse:kernel-zfcpdump6.12.0-160000.38.1 · SUSE:Linux Enterprise Server 16.0Package 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

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

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✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

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

All records