CVE-2023-3347Network attack vector

Traffic modification via unenforced SMB2 packet signing

Published Jul 20, 2023 · Updated Nov 20, 2025

Improper SMB2 signing enforcement in Samba on Red Hat Enterprise Linux 8 and 9 allows remote attackers to modify intercepted SMB2 traffic. The SMB2 server path accepts unsigned connections despite server signing = required or the equivalent mandatory Domain Controller policy. An attacker must intercept a client-server connection whose client does not require signing; IPC$ connections to Domain Controllers remain protected.

CVSS severity5.9
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper SMB2 signing enforcement in Samba on Red Hat Enterprise Linux 8 and 9 allows remote attackers to modify intercepted SMB2 traffic. The SMB2 server path accepts unsigned connections despite server signing = required or the equivalent mandatory Domain Controller policy. An attacker must intercept a client-server connection whose client does not require signing; IPC$ connections to Domain Controllers remain protected.

The record

CVE
CVE-2023-3347
Published
Jul 20, 2023
Updated
Nov 20, 2025
Vendor
Red Hat
Product
Red Hat Enterprise Linux 8
Classifications
CWE-924, CWE-347, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

6.8Samba TeamCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
5.9Red Hat, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-924Improper Enforcement of Message Integrity During Transmission in a Communication Channel
CWE-347Improper Verification of Cryptographic Signature
T1557Adversary-in-the-Middle

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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