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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | samba | 2:4.1.22+dfsg-1 | — |
| Debian 13 | samba | 2:4.1.22+dfsg-1 | — |
| Debian 12 | samba | 2:4.1.22+dfsg-1 | — |
| Debian 8 | samba | 2:4.1.17+dfsg-2+deb8u1 | DSA-3433-1 |
| Debian 7 | samba | 2:3.6.6-6+deb7u6 | DSA-3433-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | samba | 2:3.5.6~dfsg-3squeeze13 | DLA-379-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | samba | 2:4.3.3+dfsg-1ubuntu1 | — |
| Ubuntu 14.04 LTS | samba | 2:4.1.6+dfsg-1ubuntu2.14.04.11 | USN-2855-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | ctdb +26 | 4.2.3-11.el7_2 | RHSA-2016:0006 |
| RHEL 6 | samba +12 | 3.6.23-24.el6_7 | RHSA-2016:0011 |
| RHEL 6 | samba4 +13 | 4.0.0-67.el6_7.rc4 | RHSA-2016:0010 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Gluster Storage 3 | ctdb +5 | 4.2.4-9.1.el7rhgs | RHSA-2016:0016 |
| Red Hat Gluster Storage 3 | samba +20 | 4.1.17-16.el6rhs | RHSA-2016:0016, RHSA-2016:0015 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | ldb | 1.1.24-4.1 | SUSE-SU-2015:2305-1 |
| SLES 12 SP1 | samba | 4.2.4-6.1 | SUSE-SU-2015:2305-1 |
| SLES 12 SP1 | talloc | 2.1.5-4.1 | SUSE-SU-2015:2305-1 |
| SLES 12 SP1 | tdb | 1.3.8-4.1 | SUSE-SU-2015:2305-1 |
| SLES 12 SP1 | tevent | 0.9.26-4.1 | SUSE-SU-2015:2305-1 |
| SLES 12 | ldb | 1.1.24-4.3.1 | SUSE-SU-2015:2304-1 |
| SLES 12 | samba | 4.1.12-18.3.1 | SUSE-SU-2015:2304-1 |
| SLES 12 | talloc | 2.1.5-3.4.1 | SUSE-SU-2015:2304-1 |
| SLES 12 | tdb | 1.3.8-2.3.1 | SUSE-SU-2015:2304-1 |
| SLES 12 | tevent | 0.9.26-3.3.1 | SUSE-SU-2015:2304-1 |
| SLES 11 SP4 | samba +1 | 3.6.3-64.1 | SUSE-SU-2016:0164-1 |
| SLES 11 SP3 | samba +1 | 3.6.3-64.1 | SUSE-SU-2016:0164-1 |
| SLES 11 SP2 | samba +1 | 3.6.3-45.2 | SUSE-SU-2016:0032-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | ldb | 1.1.24-4.1 | SUSE-SU-2015:2305-1 |
| SLES for SAP 12 SP1 | samba | 4.2.4-6.1 | SUSE-SU-2015:2305-1 |
| SLES for SAP 12 SP1 | talloc | 2.1.5-4.1 | SUSE-SU-2015:2305-1 |
| SLES for SAP 12 SP1 | tdb | 1.3.8-4.1 | SUSE-SU-2015:2305-1 |
| SLES for SAP 12 SP1 | tevent | 0.9.26-4.1 | SUSE-SU-2015:2305-1 |
| SLES for SAP 12 | ldb | 1.1.24-4.3.1 | SUSE-SU-2015:2304-1 |
| SLES for SAP 12 | samba | 4.1.12-18.3.1 | SUSE-SU-2015:2304-1 |
| SLES for SAP 12 | talloc | 2.1.5-3.4.1 | SUSE-SU-2015:2304-1 |
| SLES for SAP 12 | tdb | 1.3.8-2.3.1 | SUSE-SU-2015:2304-1 |
| SLES for SAP 12 | tevent | 0.9.26-3.3.1 | SUSE-SU-2015:2304-1 |
| SLES for SAP 11 SP4 | samba +1 | 3.6.3-64.1 | SUSE-SU-2016:0164-1 |
| SLES for SAP 11 SP3 | samba +1 | 3.6.3-64.1 | SUSE-SU-2016:0164-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.5.0-1.1 | openSUSE-SU-2024:10069-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | samba +23 | 4.2.3-11.el7_2 | ELSA-2016-0006 |
Advisories 15
- WID-SEC-2026-3111 Samba: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 31, 2026
- RHSA-2016:0015 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2016:0016 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2016:0011 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2016:0010 Red Hat Security Advisory: samba4 security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2016:0006 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- USN-2855-1 samba vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3433-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-379-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:0164-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:2304-1 Security update for ldb, samba, talloc, tdb, tevent SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10069-1 ctdb-4.5.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:0032-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:2305-1 Security update for ldb, samba, talloc, tdb, tevent SUSE / openSUSE Security Updates · May 2, 2025
- ELSA-2016-0006 Moderate: samba security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 7, 2016
References
- https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=a819d2b440aafa3138d95ff6e8b824da885a70e9
- FEDORA-2015-0e0879cc8a vendor-advisory
- https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=1ba49b8f389eda3414b14410c7fbcb4041ca06b1
- openSUSE-SU-2016:1064 vendor-advisory
- USN-2855-2 vendor-advisory
- SUSE-SU-2016:0032 vendor-advisory
- SUSE-SU-2015:2304 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
- SUSE-SU-2015:2305 vendor-advisory
- 79732 vdb-entry
- SUSE-SU-2016:0164 vendor-advisory
- openSUSE-SU-2015:2354 vendor-advisory
- FEDORA-2015-b36076d32e vendor-advisory
- openSUSE-SU-2016:1106 vendor-advisory
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05115993
- https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=d724f835acb9f4886c0001af32cd325dbbf1f895
- 1034493 vdb-entry
- DSA-3433 vendor-advisory
- openSUSE-SU-2016:1107 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
- GLSA-201612-47 vendor-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1290292
- https://www.samba.org/samba/security/CVE-2015-5296.html
- USN-2855-1 vendor-advisory
- openSUSE-SU-2015:2356 vendor-advisory