CVE-2015-5296

Publication date 16 December 2015

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
samba	17.04 zesty	Fixed 2:4.3.3+dfsg-1ubuntu1
	16.10 yakkety	Fixed 2:4.3.3+dfsg-1ubuntu1
	16.04 LTS xenial	Fixed 2:4.3.3+dfsg-1ubuntu1
	15.10 wily	Fixed 2:4.1.17+dfsg-4ubuntu3.1
	15.04 vivid	Fixed 2:4.1.13+dfsg-4ubuntu3.1
	14.04 LTS trusty	Fixed 2:4.1.6+dfsg-1ubuntu2.14.04.11
	12.04 LTS precise	Fixed 2:3.6.3-2ubuntu2.13
samba4	17.04 zesty	Not in release
	16.10 yakkety	Not in release
	16.04 LTS xenial	Not in release
	15.10 wily	Not in release
	15.04 vivid	Not in release
	14.04 LTS trusty	Not in release
	12.04 LTS precise	Ignored end of life

Notes

mdeslaur

3.2.0 to 4.3.2 3.6 patch in upstream bug

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
samba	Upstream: https://git.samba.org/?p=samba.git;a=commit;h=d9e943e351a752ba627314da7fb8d2f6f1eb44b3 Upstream: https://git.samba.org/?p=samba.git;a=commit;h=4c3a492259ceefe3d02df690d4369291627883a2 Upstream: https://git.samba.org/?p=samba.git;a=commit;h=c634a143a876bd5a724d830c54fe12ef6d68d5fd

Severity score breakdown

Parameter	Value
Base score	5.4 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Changed
Confidentiality	Low
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

References

Related Ubuntu Security Notices (USN)

USN-2855-1
Samba vulnerabilities
5 January 2016