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NVD / CVE Program· CNA Linux

CVE-2025-22038: ksmbd: validate zero num_subauth before sub_auth is accessed

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.58% (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 0e36a3e080d6d8bd7a34e089345d043da4ac8283, 3ac65de111c686c95316ade660f8ba7aea3cd3cc, 56de7778a48560278c334077ace7b9ac4bfb2fd1; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 6.6.92.2-1.

Low priority for now. Upgrade to Linux Linux 0e36a3e080d6d8bd7a34e089345d043da4ac8283, 3ac65de111c686c95316ade660f8ba7aea3cd3cc, 56de7778a48560278c334077ace7b9ac4bfb2fd1; azl3 kernel 6.6.85.1-4 on Azure Linux 3.0 6.6.92.2-1 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: ksmbd: validate zero num_subauth before sub_auth is accessed Access psid->sub_auth[psid->num_subauth - 1] without checking if num_subauth is non-zero leads to an out-of-bounds read. This patch adds a validation step to ensure num_subauth != 0 before sub_auth is accessed.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Apr 16, 2025
Updated
Aug 5, 2026
EPSS
0.5% · 48th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.1
CNA · Linux
8.3
1.2 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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-2025-22038

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • 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

Affected versions

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

  • linux linux kernelbefore 6.1.134
  • linux linux kernel6.2 and later · before 6.6.87
  • linux linux kernel6.7 and later · before 6.12.23
  • linux linux kernel6.13 and later · before 6.13.11
  • linux linux kernel6.14 and later · before 6.14.2

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

    • 5.15affected
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 3ac65de111c686c95316ade660f8ba7aea3cd3ccaffected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 0e36a3e080d6d8bd7a34e089345d043da4ac8283affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 56de7778a48560278c334077ace7b9ac4bfb2fd1affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before 68c6c3142bfcdb049839d40a9a59ebe8ea865002affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before c8bfe1954a0b89e7b29b3a3e7f4c5e0ebd295e20affected · git
    • 0626e6641f6b467447c81dd7678a69c66f7746cf and later · before bf21e29d78cd2c2371023953d9c82dfef82ebb36affected · git
    • before 5.15not affected · semver
    • 6.1.134 and later · up to and including 6.1.*not affected · semver
    • 6.6.87 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 6.1.135-16.1.135-1
Debian:13linuxbefore 6.12.25-16.12.25-1

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-2025-22035Apr 16, 2025 · tracing: Fix use-after-free in print_graph_function_flags during tracer switching
    31Monitor
  • ← EarlierCVE-2025-22036Apr 16, 2025 · exfat: fix random stack corruption after get_block
    28Monitor
  • Later →CVE-2025-22039Apr 16, 2025 · ksmbd: fix overflow in dacloffset bounds check
    28Monitor

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 Linux0e36a3e080d6d8bd7a34e089345d043da4ac8283Vendor (CNA)
Linux Linux3ac65de111c686c95316ade660f8ba7aea3cd3ccVendor (CNA)
Linux Linux56de7778a48560278c334077ace7b9ac4bfb2fd1Vendor (CNA)
Linux Linux68c6c3142bfcdb049839d40a9a59ebe8ea865002Vendor (CNA)
Linux Linuxbf21e29d78cd2c2371023953d9c82dfef82ebb36Vendor (CNA)
Linux Linuxc8bfe1954a0b89e7b29b3a3e7f4c5e0ebd295e20Vendor (CNA)
azl3 kernel 6.6.85.1-4 on Azure Linux 3.06.6.92.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.135-1 · 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.

No history yet (it accumulates with the daily EPSS job).

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).

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
high · data can be read
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
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records