CVE-2023-3347: Samba: smb2 packet signing is not enforced when "server signing = required" is set
Vulnerability summary
CVE-2023-3347 is a medium (CVSS 5.9) vulnerability in fedoraproject fedora. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.9% of scored vulnerabilities.
Not severe (CVSS 5.9, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 5 · Related 3Timeline
- 20-07-2023PublishedVulnerability first disclosed.
- 20-11-2025Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · Red hatEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · UbuntuEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · DebianEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- NVDNIST5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS trend
Probability
0.44%
Chance of exploitation in the next 30 days
Percentile
38%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.44% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-347Improper Verification of Cryptographic SignatureThe product does not verify, or incorrectly verifies, the cryptographic signature for data.
- CWE-924Improper Enforcement of Message Integrity During Transmission in a Communication ChannelThe product establishes a communication channel with an endpoint and receives a message from that endpoint, but it does not sufficiently ensure that the message was not modified during transmission.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat61 products
- enterprise_linux8.0 | 9.0
- storage3.0
- ctdb< 0:4.17.5-103.el9_2 | < 0:4.17.5-3.el8_8
- ctdb-debuginfo< 0:4.17.5-103.el9_2 | < 0:4.17.5-3.el8_8
- libnetapi< 0:4.17.5-103.el9_2 | < 0:4.17.5-3.el8_8
Debian1 product
- samba< 2:4.17.10+dfsg-0+deb12u1 | < 2:4.18.5+dfsg-1
Fedoraproject1 product
- fedoraEOL38
Samba1 product
- samba≥ 4.17.0, < 4.17.10 | ≥ 4.18.0, < 4.18.5
Ubuntu1 product
- samba< 2:4.15.13+dfsg-0ubuntu0.20.04.2 | < 2:4.15.13+dfsg-0ubuntu1.1
5 vendors · 65 products
References
19 links- access.redhat.com/errata/RHSA-2023:4325Vendor AdvisoryX Refsource REDHATAdvisoryThird Party Advisory
- access.redhat.com/errata/RHSA-2023:4328Vendor AdvisoryX Refsource REDHATAdvisoryThird Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2222792Issue TrackingX Refsource REDHATREPORTThird Party Advisory
- lists.fedoraproject.org/archives/…X Transferred
- lists.fedoraproject.org/archives/…X Transferred
- security.netapp.com/advisory/ntap-20230731-0010/X Transferred
www.debian.org/security/2023/dsa-5477X Transferred
