Skip to content
Fencer Vulns
medium 5.9

CVE-2023-3347 json

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

published 2023-07-20 3 y ago modified 2026-11-07 2 d ago also EUVD-2023-44015

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 8 0:4.17.5-3.el8_8
  • Red Hat Red Hat Enterprise Linux 9 0:4.17.5-103.el9_2
  • samba Debian 12 2:4.17.10+dfsg-0+deb12u1
  • samba Debian 14, Debian 13 2:4.18.5+dfsg-1

debian advisories DEBIAN-CVE-2023-3347

  • samba RHEL 9 4.17.5-103.el9_2
  • ctdb RHEL 9 4.17.5-103.el9_2
  • libnetapi RHEL 9 4.17.5-103.el9_2
  • samba-libs RHEL 9 4.17.5-103.el9_2
  • samba-pidl RHEL 9 4.17.5-103.el9_2
  • samba-test RHEL 9 4.17.5-103.el9_2
  • libwbclient RHEL 9 4.17.5-103.el9_2
  • samba-tools RHEL 9 4.17.5-103.el9_2

red hat advisories RHSA-2023:4325RHSA-2023:4328

  • samba SLE Module for Basesystem 15 SP5, SLE High Availability Extension 15 SP5, openSUSE Leap 15.5 4.17.9+git.367.dae41ffdd1f-150500.3.5.1

suse advisories SUSE-SU-2023:2929-1

  • samba openSUSE Tumbleweed 4.18.5+git.313.c8e274c7852-1.1

opensuse advisories openSUSE-SU-2024:13071-1

  • samba AlmaLinux 9 4.17.5-103.el9_2.alma
  • ctdb AlmaLinux 9 4.17.5-103.el9_2.alma
  • libnetapi AlmaLinux 9 4.17.5-103.el9_2.alma
  • samba-libs AlmaLinux 9 4.17.5-103.el9_2.alma
  • samba-pidl AlmaLinux 9 4.17.5-103.el9_2.alma
  • samba-test AlmaLinux 9 4.17.5-103.el9_2.alma
  • libwbclient AlmaLinux 9 4.17.5-103.el9_2.alma
  • samba-tools AlmaLinux 9 4.17.5-103.el9_2.alma

almalinux advisories ALSA-2023:4325ALSA-2023:4328

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-3347 updated cvss 5.9

samba: SMB2 packet signing is not enforced when "server signing = required" is set

  • Red Hat Storage 3 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +21 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) samba-vfs-iouring 4.17.5-3.el8_8
    fixed: vendor fix RHSA-2023:4328
  • Red Hat Enterprise Linux AppStream (v. 9) samba-client 4.17.5-103.el9_2, samba-winexe 4.17.5-103.el9_2, samba-vfs-iouring 4.17.5-103.el9_2, samba-krb5-printing 4.17.5-103.el9_2, samba-winbind-clients 4.17.5-103.el9_2, samba-winbind-krb5-locator 4.17.5-103.el9_2
    fixed: vendor fix RHSA-2023:4325
  • Red Hat Enterprise Linux BaseOS (v. 8) ctdb 4.17.5-3.el8_8, samba 4.17.5-3.el8_8, libnetapi 4.17.5-3.el8_8, samba-libs 4.17.5-3.el8_8, samba-pidl 4.17.5-3.el8_8, samba-test 4.17.5-3.el8_8, +22 more
    fixed: vendor fix RHSA-2023:4328
  • Red Hat Enterprise Linux BaseOS (v. 9) samba 4.17.5-103.el9_2, libnetapi 4.17.5-103.el9_2, samba-libs 4.17.5-103.el9_2, libwbclient 4.17.5-103.el9_2, samba-tools 4.17.5-103.el9_2, libsmbclient 4.17.5-103.el9_2, +12 more
    fixed: vendor fix RHSA-2023:4325
  • Red Hat Enterprise Linux CRB (v. 8) samba-devel 4.17.5-3.el8_8, ctdb-debuginfo 4.17.5-3.el8_8, libnetapi-devel 4.17.5-3.el8_8, samba-debuginfo 4.17.5-3.el8_8, libwbclient-devel 4.17.5-3.el8_8, samba-debugsource 4.17.5-3.el8_8, +24 more
    fixed: vendor fix RHSA-2023:4328
  • Red Hat Enterprise Linux CRB (v. 9) samba-pidl 4.17.5-103.el9_2, samba-test 4.17.5-103.el9_2, samba-test-libs 4.17.5-103.el9_2, python3-samba-test 4.17.5-103.el9_2 Red Hat Enterprise Linux ResilientStorage (v. 9) ctdb 4.17.5-103.el9_2
    fixed: vendor fix RHSA-2023:4325
  • Red Hat Enterprise Linux 6 samba, samba4, samba4-dc, samba-swat, samba4-libs, samba4-pidl, +17 more Red Hat Enterprise Linux 7 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +18 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Storage 3

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-924 Improper Enforcement of Message Integrity During Transmission in a Communication Channel

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.