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NVD / CVE Program· CNA Linux

CVE-2026-43228: hfs: Replace BUG_ON with error handling for CNID count checks

MediumCVSS 5.5 · v3.1—No exploit Fix available

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: 0.12% (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 559f856b109c45844816a1693e259f93d3556c61, b226804532a875c10276168dc55ce752944096bd, b6536c1ced315fa645576d3a39c6e07f2a472962; azl3 kernel 6.6.137.1-2 on Azure Linux 3.0 6.6.137.1-2.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 559f856b109c45844816a1693e259f93d3556c61, b226804532a875c10276168dc55ce752944096bd, b6536c1ced315fa645576d3a39c6e07f2a472962; azl3 kernel 6.6.137.1-2 on Azure Linux 3.0 6.6.137.1-2 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: hfs: Replace BUG_ON with error handling for CNID count checks In a06ec283e125 next_id, folder_count, and file_count in the super block info were expanded to 64 bits, and BUG_ONs were added to detect overflow. This triggered an error reported by syzbot: if the MDB is corrupted, the BUG_ON is triggered. This patch replaces this mechanism with proper error handling and resolves the syzbot reported bug. Singed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>

Published
May 6, 2026
Updated
Nov 11, 2026
EPSS
0.1% · 2th 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%

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-43228

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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

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

    • 6.18affected
    • a06ec283e125e334155fe13005c76c9f484ce759 and later · before 559f856b109c45844816a1693e259f93d3556c61affected · git
    • a06ec283e125e334155fe13005c76c9f484ce759 and later · before b6536c1ced315fa645576d3a39c6e07f2a472962affected · git
    • a06ec283e125e334155fe13005c76c9f484ce759 and later · before b226804532a875c10276168dc55ce752944096bdaffected · git
    • before 6.18not affected · semver
    • 6.18.57 and later · up to and including 6.18.*not affected · semver
    • 6.19.6 and later · up to and including 6.19.*not affected · semver
    • 7.0 and laternot affected · original_commit_for_fix

Affected versions

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

  • linux linux kernel6.18 and later · before 6.19.6

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 6.19.6-16.19.6-1

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-2026-43226May 6, 2026 · net/rds: No shortcut out of RDS_CONN_ERROR
    30Monitor
  • ← EarlierCVE-2026-43227May 6, 2026 · clocksource/drivers/sh_tmu: Always leave device running after probe
    22Monitor
  • Later →CVE-2026-43229May 6, 2026 · media: chips-media: wave5: Fix device cleanup order to prevent kernel panic
    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 Linux559f856b109c45844816a1693e259f93d3556c61Vendor (CNA)
Linux Linuxb226804532a875c10276168dc55ce752944096bdVendor (CNA)
Linux Linuxb6536c1ced315fa645576d3a39c6e07f2a472962Vendor (CNA)
azl3 kernel 6.6.137.1-2 on Azure Linux 3.06.6.137.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.19.6-1 · Debian:14Package 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.

Variant candidates

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

  • CVE-2026-317395 days apartcrypto: tegra - Add missing CRYPTO_ALG_ASYNC
    35Monitor
  • CVE-2026-5295249 days apartiommu: Fix WARN_ON in __iommu_group_set_domain_nofail() due to reset
    35Monitor
  • CVE-2026-4611722 days apartRDMA/mana: Remove user triggerable WARN_ON() in mana_ib_create_qp_rss()
    31Monitor
  • CVE-2026-3139833 days apartmm/rmap: fix incorrect pte restoration for lazyfree folios
    31Monitor
  • CVE-2025-39803233 days apartscsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl()
    31Monitor
  • CVE-2026-4602721 days apartnet/smc: avoid early lgr access in smc_clc_wait_msg
    30Monitor

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

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-617 · Reachable Assertion

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.

References

Show all references (2 more)

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

All records