What’s Vulnerable › Vulnerabilities

CVE-2015-5296

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 7.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2015-12-29 · updated 2026-06-17
• Weakness: CWE-20

Description

Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3 supports connections that are encrypted but unsigned, which allows man-in-the-middle attackers to conduct encrypted-to-unencrypted downgrade attacks by modifying the client-server data stream, related to clidfs.c, libsmb_server.c, and smbXcli_base.c.

Affected products

• Canonical Ubuntu Linux: 12.04, 14.04, 15.04, 15.10
• Debian Linux: 7.0, 8.0
• Samba: from 3.2.0 before 4.1.22; from 4.2.0 before 4.2.7; from 4.3.0 before 4.3.3 — fixed in 4.1.22, 4.2.7, 4.3.3

How to fix

Upgrade to a fixed version: Samba 4.1.22, 4.2.7, 4.3.3. Check the vendor advisory for mitigations.

References

• http://lists.fedoraproject.org/pipermail/package-announce/2015-December/174076.html
• http://lists.fedoraproject.org/pipermail/package-announce/2015-December/174391.html
• http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00019.html
• http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00020.html
• http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00032.html
• http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00033.html
• http://lists.opensuse.org/opensuse-security-announce/2016-01/msg00002.html
• http://lists.opensuse.org/opensuse-security-announce/2016-01/msg00017.html
• http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00042.html
• http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00047.html
• http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00048.html
• http://www.debian.org/security/2016/dsa-3433

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