CVE-2023-38428Network attack vector

Unauthenticated kernel data disclosure via username bounds error

Published Jul 17, 2023 · Updated Oct 15, 2024

An out-of-bounds read in Linux kernel ksmbd before 6.3.4 allows remote attackers to disclose kernel data through SMB session setup. The session_user function validates the untrusted UserName offset and length against a size that includes SecurityBufferOffset, then reads from the security buffer base. An unauthenticated SMB client can reach this path, causing sensitive-data exposure or a system crash without modifying data.

CVSS severity9.1
Critical
EPSS probability3.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in Linux kernel ksmbd before 6.3.4 allows remote attackers to disclose kernel data through SMB session setup. The session_user function validates the untrusted UserName offset and length against a size that includes SecurityBufferOffset, then reads from the security buffer base. An unauthenticated SMB client can reach this path, causing sensitive-data exposure or a system crash without modifying data.

The record

CVE
CVE-2023-38428
Published
Jul 17, 2023
Updated
Oct 15, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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