CVE-2026-3238Network attack vector

WINS service crash via malformed UDP packet

Published Jun 8, 2026 · Updated Jun 8, 2026

NULL pointer dereference in the Samba WINS server allows remote attackers to crash the service using a crafted UDP packet. The RELEASE and MULTI_HOME_REG handlers fail to validate requests before dereferencing a NULL pointer, causing repeated service restarts at increasing intervals. The flaw is reachable only on an Active Directory Domain Controller with WINS support explicitly enabled, and repeated packets can keep WINS completely unavailable.

CVSS severity7.5
High
EPSS probability2.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Samba WINS server allows remote attackers to crash the service using a crafted UDP packet. The RELEASE and MULTI_HOME_REG handlers fail to validate requests before dereferencing a NULL pointer, causing repeated service restarts at increasing intervals. The flaw is reachable only on an Active Directory Domain Controller with WINS support explicitly enabled, and repeated packets can keep WINS completely unavailable.

The record

CVE
CVE-2026-3238
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 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?

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

7.5Samba TeamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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