CVE Vulnerabilities


Out-of-bounds Read

Published: Jan 21, 2020 | Modified: May 29, 2021
CVSS 3.x
CVSS 2.x
2.6 LOW

All samba versions 4.9.x before 4.9.18, 4.10.x before 4.10.12 and 4.11.x before 4.11.5 have an issue where if it is set with log level = 3 (or above) then the string obtained from the client, after a failed character conversion, is printed. Such strings can be provided during the NTLMSSP authentication exchange. In the Samba AD DC in particular, this may cause a long-lived process(such as the RPC server) to terminate. (In the file server case, the most likely target, smbd, operates as process-per-client and so a crash there is harmless).


The software reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name Vendor Start Version End Version
Samba Samba 4.9.0 *
Samba Samba 4.10.0 *
Samba Samba 4.11.0 *
Fedora Fedoraproject 30 30
Fedora Fedoraproject 31 31
Red Hat Enterprise Linux 7 RedHat samba-0:4.10.16-5.el7 *
Red Hat Enterprise Linux 8 RedHat openchange-0:2.3-24.el8 *
Red Hat Enterprise Linux 8 RedHat samba-0:4.11.2-13.el8 *
Red Hat Gluster Storage 3.5 for RHEL 7 RedHat libtalloc-0:2.2.0-9.el7rhgs *
Red Hat Gluster Storage 3.5 for RHEL 7 RedHat libtdb-0:1.4.2-4.el7rhgs *
Red Hat Gluster Storage 3.5 for RHEL 7 RedHat libtevent-0:0.10.0-4.el7rhgs *
Red Hat Gluster Storage 3.5 for RHEL 7 RedHat samba-0:4.11.6-104.el7rhgs *
Samba Ubuntu bionic *
Samba Ubuntu devel *
Samba Ubuntu disco *
Samba Ubuntu eoan *
Samba Ubuntu esm-infra/xenial *
Samba Ubuntu focal *
Samba Ubuntu groovy *
Samba Ubuntu hirsute *
Samba Ubuntu impish *
Samba Ubuntu jammy *
Samba Ubuntu precise/esm *
Samba Ubuntu trusty *
Samba Ubuntu upstream *
Samba Ubuntu xenial *

Potential Mitigations

  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.