Samba: smb2 packet signing is not enforced when "server signing = required" is set

Description

A vulnerability was found in Samba's SMB2 packet signing mechanism. The SMB2 packet signing is not enforced if an admin configured "server signing = required" or for SMB2 connections to Domain Controllers where SMB2 packet signing is mandatory. This flaw allows an attacker to perform attacks, such as a man-in-the-middle attack, by intercepting the network traffic and modifying the SMB2 messages between client and server, affecting the integrity of the data.

Scores

EPSS (exploitation in 30 days)

0.44% · top 62% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

• CWE-347: Improper Verification of Cryptographic Signature (opens in a new tab)All about CWE-347 and its CVEs
• CWE-924 Improper Enforcement of Message Integrity During Transmission in a Communication Channel (opens in a new tab)All about CWE-924 and its CVEs

Affected products

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:4.17.5-3.el8_8 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:4.17.5-3.el8_8 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:4.17.5-103.el9_2 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:4.17.5-103.el9_2 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unaffected

• Red Hat · Red Hat Enterprise Linux 7

  All versions: unaffected

• Red Hat · Red Hat Storage 3

  All versions: unknown

References (9)

• RHSA-2023:4325 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• RHSA-2023:4328 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
• https://access.redhat.com/security/cve/CVE-2023-3347 (opens in a new tab)vdb-entryx_refsource_REDHATx_transferred
• RHBZ#2222792 (opens in a new tab)issue-trackingx_refsource_REDHATx_transferred
• https://www.samba.org/samba/security/CVE-2023-3347.html (opens in a new tab)x_transferred
• https://lists.fedoraproject.org/archives/list/[email protected]/message/BPCSGND7LO467AJGR5DYBGZLTCGTOBCC/ (opens in a new tab)x_transferred
• https://lists.fedoraproject.org/archives/list/[email protected]/message/OT74M42E6C36W7PQVY3OS4ZM7DVYB64Z/ (opens in a new tab)x_transferred
• https://security.netapp.com/advisory/ntap-20230731-0010/ (opens in a new tab)x_transferred
• https://www.debian.org/security/2023/dsa-5477 (opens in a new tab)x_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2023-3347](https://trackcve.app/badge/CVE-2023-3347.svg)](https://trackcve.app/cve/CVE-2023-3347)

Record last updated 7 Nov 2026, 05:01 UTC.