CVE-2015-7540

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 7.1% 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-399

Description

The LDAP server in the AD domain controller in Samba 4.x before 4.1.22 does not check return values to ensure successful ASN.1 memory allocation, which allows remote attackers to cause a denial of service (memory consumption and daemon crash) via crafted packets.

Affected products

Canonical Ubuntu Linux: 12.04, 14.04, 15.04, 15.10
Debian Linux: 7.0, 8.0
Samba: from 4.0.0 before 4.1.22 — fixed in 4.1.22

How to fix

Upgrade to a fixed version: Samba 4.1.22. 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/msg00033.html
http://www.debian.org/security/2016/dsa-3433
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
http://www.securityfocus.com/bid/79736
http://www.securitytracker.com/id/1034492
http://www.ubuntu.com/usn/USN-2855-1
http://www.ubuntu.com/usn/USN-2855-2
https://bugzilla.redhat.com/show_bug.cgi?id=1288451
https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=530d50a1abdcdf4d1775652d4c456c1274d83d8d
https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=9d989c9dd7a5b92d0c5d65287935471b83b6e884

Get alerted when CVE-2015-7540 or the next vulnerability affects your stack