As per upstream: A string in an LDAP attribute that contains multiple consecutive leading spaces can lead to a memmove() of out of bounds memory in ldb_handler_fold(). ldb_handler_fold() is used by case insensitive strings - that is most string attributes - in Active Directory. As the search expression is normalised prior to matching any potential objects this in turn may crash the LDAP server process handling the request. It may be possible to leak the out of bounds memory by matching against it, but this is thought to be unlikely.
Acknowledgments: Name: the Samba Project Upstream: Douglas Bagnall (Catalyst and the Samba Team)
Created libldb tracking bugs for this issue: Affects: fedora-all [bug 1942497]
External References: http://www.samba.org/samba/security/CVE-2021-20277.html
Upstream patch: http://github.com/samba-team/samba/commit/fab6b79b7724f0b636963be528483e3e946884aa
Red Hat Gluster Storage 3 uses built-in version of ldb library in Samba: $ cat samba.spec [...] # RHGS always builds with a private copy of ldb %global with_internal_ldb 1 [...] %if ! %with_internal_ldb %global libldb_version 2.0.8 BuildRequires: libldb-devel >= %{libldb_version} BuildRequires: python3-ldb-devel >= %{libldb_version} %endif [...]
Statement: The version of Samba shipped with Red Hat Gluster Storage (RHGS) 3 is built with a private copy of ldb (LDAP-like embedded database) library which includes the vulnerable code. However, Samba shipped with RHGS 3 is not supported for use as an Active Directory Domain Controller and hence the impact has been lowered.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2021:1072 http://access.redhat.com/errata/RHSA-2021:1072
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): http://access.redhat.com/security/cve/cve-2021-20277
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2021:1197 http://access.redhat.com/errata/RHSA-2021:1197
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.1 Extended Update Support Via RHSA-2021:1214 http://access.redhat.com/errata/RHSA-2021:1214
This issue has been addressed in the following products: Red Hat Enterprise Linux 8.2 Extended Update Support Via RHSA-2021:1213 http://access.redhat.com/errata/RHSA-2021:1213
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.7 Extended Update Support Via RHSA-2021:2331 http://access.redhat.com/errata/RHSA-2021:2331
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.6 Advanced Update Support Red Hat Enterprise Linux 7.6 Update Services for SAP Solutions Red Hat Enterprise Linux 7.6 Telco Extended Update Support Via RHSA-2021:2786 http://access.redhat.com/errata/RHSA-2021:2786