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NVD / CVE Program· CNA Linux

CVE-2023-4515: ksmbd: validate command request size

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: 0.31% (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 5.15.127, 595679098bdcdbfbba91ebe07a2f7f208df93870, 5aa4fda5aa9c2a5a7bac67b4a12b089ab81fee3c.
  • Severity is disputed: the assigning authority (CNA) scores it 9.1, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 5.15.127, 595679098bdcdbfbba91ebe07a2f7f208df93870, 5aa4fda5aa9c2a5a7bac67b4a12b089ab81fee3c 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 command request size In commit 2b9b8f3b68ed ("ksmbd: validate command payload size"), except for SMB2_OPLOCK_BREAK_HE command, the request size of other commands is not checked, it's not expected. Fix it by add check for request size of other commands.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Aug 16, 2025
Updated
Aug 5, 2026
EPSS
0.3% · 23th percentile
CWE
—

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 · 0.3%

CNA vs NVD score

NVD
5.5
CNA · Linux
9.1
3.6 point gap

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

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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 kernel5.15.121 and later · before 5.15.127
  • linux linux kernel6.1.36 and later · before 6.1.46
  • linux linux kernel6.3.10 and later · before 6.4
  • linux linux kernel6.4.1 and later · before 6.4.11
  • linux linux kernel6.4
  • linux linux kernel6.5

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

    • 768caf4019f0391c0b6452afe34cea1704133f7b, 6.4affected
    • 35f450f54dca1519bb24faacd0428db09f89a11f and later · before 595679098bdcdbfbba91ebe07a2f7f208df93870affected · git
    • 9650cf70ec9d94ff34daa088b643229231723c26 and later · before c6bef3bc30fd4a175aef846b7d928a6c40d091cdaffected · git
    • 2b9b8f3b68edb3d67d79962f02e26dbb5ae3808d and later · before ff7236b66d69582f90cf5616e63cfc3dc18142bbaffected · git
    • 2b9b8f3b68edb3d67d79962f02e26dbb5ae3808d and later · before 5aa4fda5aa9c2a5a7bac67b4a12b089ab81fee3caffected · git
    • 5.15.121 and later · before 5.15.127affected · semver
    • 6.1.36 and later · before 6.1.46affected · semver
    • 6.3.10 and later · before 6.4affected · semver
    • before 6.4not affected · semver
    • 5.15.127 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.52-16.1.52-1
Debian:13linuxbefore 6.4.11-16.4.11-1
openSUSE:Leap 15.6dtb-aarch64before 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-64kbbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-azurebefore 6.4.0-150600.8.52.16.4.0-150600.8.52.1
openSUSE:Leap 15.6kernel-debugbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-defaultbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-default-basebefore 6.4.0-150600.23.70.1.150600.12.30.26.4.0-150600.23.70.1.150600.12.30.2
openSUSE:Leap 15.6kernel-docsbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-kvmsmallbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-obs-buildbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-obs-qabefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-rtbefore 6.4.0-150600.10.52.16.4.0-150600.10.52.1
openSUSE:Leap 15.6kernel-rt_debugbefore 6.4.0-150600.10.52.16.4.0-150600.10.52.1
openSUSE:Leap 15.6kernel-sourcebefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-source-azurebefore 6.4.0-150600.8.52.16.4.0-150600.8.52.1
openSUSE:Leap 15.6kernel-source-rtbefore 6.4.0-150600.10.52.16.4.0-150600.10.52.1
openSUSE:Leap 15.6kernel-symsbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
openSUSE:Leap 15.6kernel-syms-azurebefore 6.4.0-150600.8.52.16.4.0-150600.8.52.1
openSUSE:Leap 15.6kernel-syms-rtbefore 6.4.0-150600.10.52.16.4.0-150600.10.52.1
openSUSE:Leap 15.6kernel-zfcpdumpbefore 6.4.0-150600.23.70.16.4.0-150600.23.70.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_15before 1-150600.13.3.21-150600.13.3.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6-RT_Update_15before 1-150600.1.3.11-150600.1.3.1
SUSE:Linux Enterprise Live Patching 15 SP7kernel-livepatch-SLE15-SP7_Update_4before 1-150700.15.3.21-150700.15.3.2

+40

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-2023-3867Aug 16, 2025 · ksmbd: fix out of bounds read in smb2_sess_setup
    30Monitor
  • ← EarlierCVE-2023-4130Aug 16, 2025 · ksmbd: fix wrong next length validation of ea buffer in smb2_set_ea()
    22Monitor
  • Later →CVE-2025-38505Aug 16, 2025 · wifi: mwifiex: discard erroneous disassoc frames on STA interface
    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 Linux5.15.127Vendor (CNA)
Linux Linux595679098bdcdbfbba91ebe07a2f7f208df93870Vendor (CNA)
Linux Linux5aa4fda5aa9c2a5a7bac67b4a12b089ab81fee3cVendor (CNA)
Linux Linux6.1.46Vendor (CNA)
Linux Linux6.4Vendor (CNA)
Linux Linuxc6bef3bc30fd4a175aef846b7d928a6c40d091cdVendor (CNA)
Linux Linuxff7236b66d69582f90cf5616e63cfc3dc18142bbVendor (CNA)
debian:linux6.1.52-1 · Debian:12Package registry (OSV)
opensuse:dtb-aarch646.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-64kb6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-debug6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-default6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-default-base6.4.0-150600.23.70.1.150600.12.30.2 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-docs6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-kvmsmall6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-obs-build6.4.0-150600.23.70.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-rt6.4.0-150600.10.52.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-rt_debug6.4.0-150600.10.52.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-source-rt6.4.0-150600.10.52.1 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:kernel-syms-rt6.4.0-150600.10.52.1 · openSUSE:Leap 15.6Package registry (OSV)
suse:kernel-64kb6.4.0-150600.23.70.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP6Package registry (OSV)
suse:kernel-64kb6.4.0-150700.53.16.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-default6.4.0-150600.23.70.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP6Package registry (OSV)
suse:kernel-default6.4.0-150700.53.16.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-default-base6.4.0-150600.23.70.1.150600.12.30.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP6Package registry (OSV)
suse:kernel-default-base6.4.0-150700.53.16.1.150700.17.11.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7Package registry (OSV)
suse:kernel-docs6.4.0-150700.53.16.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6-RT_Update_151-150600.1.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-obs-build6.4.0-150700.53.16.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)
suse:kernel-rt6.4.0-150600.10.52.1 · SUSE:Real Time Module 15 SP6Package registry (OSV)

+5

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).

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)

—

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 (3 more)

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

All records