An ldb security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

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Ubuntu Security Notice USN-4888-1
March 24, 2021

ldb vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in ldb.

Software Description:
- ldb: None

Details:

Douglas Bagnall discovered that ldb, when used with Samba, incorrectly
handled certain LDAP attributes. A remote attacker could possibly use this
issue to cause the LDAP server to crash, resulting in a denial of service.
(CVE-2021-20277)

Douglas Bagnall discovered that ldb, when used with Samba, incorrectly
handled certain DN strings. A remote attacker could use this issue to
cause the LDAP server to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2020-27840)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.10:
libldb2 2:2.1.4-2ubuntu0.1

Ubuntu 20.04 LTS:
libldb2 2:2.0.10-0ubuntu0.20.04.3

Ubuntu 18.04 LTS:
libldb1 2:1.2.3-1ubuntu0.2

Ubuntu 16.04 LTS:
libldb1 2:1.1.24-1ubuntu3.2

After a standard system update you need to restart applications using ldb,
such as Samba, to make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-4888-1
CVE-2020-27840, CVE-2021-20277

Package Information:
  https://launchpad.net/ubuntu/+source/ldb/2:2.1.4-2ubuntu0.1
  https://launchpad.net/ubuntu/+source/ldb/2:2.0.10-0ubuntu0.20.04.3
  https://launchpad.net/ubuntu/+source/ldb/2:1.2.3-1ubuntu0.2
  https://launchpad.net/ubuntu/+source/ldb/2:1.1.24-1ubuntu3.2