CVE-2023-32251

Kernel: ksmbd brute force delay bypass via asynchronous requests

Published Jul 31, 2025 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed

Description

A vulnerability has been identified in the Linux kernel's ksmbd component (kernel SMB/CIFS server). A security control designed to prevent dictionary attacks, which introduces a 5-second delay during session setup, can be bypassed through the use of asynchronous requests. This bypass negates the intended anti-brute-force protection, potentially allowing attackers to conduct dictionary attacks more efficiently against user credentials or other authentication mechanisms.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

unaffected

Version	Status	Constraints
`0`	affected	< 5.15.145
`6.0.0`	affected	< 6.0.*
`6.1.0`	affected	< 6.1.29
`6.2.0`	affected	< 6.2.16
`6.3.0`	affected	< 6.3.2

Red Hat Red Hat Enterprise Linux 10 unaffected —

Red Hat Red Hat Enterprise Linux 6 unaffected —

Red Hat Red Hat Enterprise Linux 7 unaffected —

Red Hat Red Hat Enterprise Linux 8 unaffected —

Red Hat Red Hat Enterprise Linux 9 unaffected —

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2023-36508	A vulnerability has been identified in the Linux kernel's ksmbd component (kernel SMB/CIFS server). A security control designed to prevent dictionary attacks, which introduces a 5-second delay during session setup, can be bypassed through the use of asynchronous requests. This bypass negates the intended anti-brute-force protection, potentially allowing attackers to conduct dictionary attacks more efficiently against user credentials or other authentication mechanisms.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.494% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://access.redhat.com/security/cve/CVE-2023-32251
https://bugzilla.redhat.com/show_bug.cgi?id=2385852
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b096d97f47326b1e2dbdef1c91fab69ffda54d17
https://www.zerodayinitiative.com/advisories/ZDI-23-699/

History

Nov 9, 2026 3:30 AM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Redhat rhel Els
CPEs	cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:enterprise_linux:9	cpe:/a:redhat:enterprise_linux:10 cpe:/a:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:rhel_els:6 cpe:/o:redhat:rhel_els:7
Vendors & Products		Redhat rhel Els

Jun 30, 2026 7:15 AM Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
CPEs	~~cpe:/o:redhat:rhivos:1~~
Vendors & Products	Redhat rhivos

Jun 25, 2026 6:45 AM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Redhat rhivos
CPEs		cpe:/o:redhat:rhivos:1
Vendors & Products		Redhat rhivos

Nov 21, 2025 6:15 AM Added references View changes

Type	Values Removed	Values Added
References		https://access.redhat.com/security/cve/CVE-2023-32251 https://bugzilla.redhat.com/show_bug.cgi?id=2385852

Aug 1, 2025 2:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Aug 1, 2025 1:30 AM References updated View changes

Type	Values Removed	Values Added
References	https://access.redhat.com/security/cve/CVE-2023-32251 https://bugzilla.redhat.com/show_bug.cgi?id=2385852

Jul 31, 2025 9:00 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A vulnerability has been identified in the Linux kernel's ksmbd component (kernel SMB/CIFS server). A security control designed to prevent dictionary attacks, which introduces a 5-second delay during session setup, can be bypassed through the use of asynchronous requests. This bypass negates the intended anti-brute-force protection, potentially allowing attackers to conduct dictionary attacks more efficiently against user credentials or other authentication mechanisms.
Title		Kernel: ksmbd brute force delay bypass via asynchronous requests
First Time appeared		Redhat Redhat enterprise Linux
Weaknesses		CWE-307
CPEs		cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:enterprise_linux:9
Vendors & Products		Redhat Redhat enterprise Linux
References		https://access.redhat.com/security/cve/CVE-2023-32251 https://bugzilla.redhat.com/show_bug.cgi?id=2385852 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b096d97f47326b1e2dbdef1c91fab69ffda54d17 https://www.zerodayinitiative.com/advisories/ZDI-23-699/
Metrics		cvssV3_1 `{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}`