CVE-2023-52479Network attack vector

Authenticated kernel code execution via oplock use-after-free

Published Feb 29, 2024 · Updated Aug 15, 2026

Use-after-free in Linux ksmbd 5.15 through 6.5 allows remote authenticated users to execute kernel code via an SMB oplock-break acknowledgment. The smb20_oplock_break_ack function drops opinfo and file references before writing op_state and waking the freed object's wait queue. A basic authenticated share session, including an enabled guest session, can reach the sequence and disclose or corrupt kernel memory or crash the server.

CVSS severity7.1
High
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux ksmbd 5.15 through 6.5 allows remote authenticated users to execute kernel code via an SMB oplock-break acknowledgment. The smb20_oplock_break_ack function drops opinfo and file references before writing op_state and waking the freed object's wait queue. A basic authenticated share session, including an enabled guest session, can reach the sequence and disclose or corrupt kernel memory or crash the server.

The record

CVE
CVE-2023-52479
Published
Feb 29, 2024
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 29, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.15
  2. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <694e13732e830cbbfedb562e57f28644927c33fd
  3. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <8226ffc759ea59f10067b9acdf7f94bae1c69930
  4. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <c69813471a1ec081a0b9bf0c6bd7e8afd818afce
  5. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <d5b0e9d3563e7e314a850e81f42b2ef6f39882f9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <694e13732e830cbbfedb562e57f28644927c33fd; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <8226ffc759ea59f10067b9acdf7f94bae1c69930; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <c69813471a1ec081a0b9bf0c6bd7e8afd818afce; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <d5b0e9d3563e7e314a850e81f42b2ef6f39882f9

Published CVSS scores

7.1UbuntuCVSS:3.1/AV:L/AC:L/PR:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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