==========================================================================
Ubuntu Security Notice USN-7588-1
June 23, 2025

gss-ntlmssp vulnerabilities
==========================================================================

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

- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in GSS NTLMSSP.

Software Description:
- gss-ntlmssp: A mechglue plugin for the GSSAPI library that implements NTLM authentication

Details:

Phil Turnbull discovered that GSS NTLMSSP may perform out-of-bounds reads 
when decoding NTLM fields and target information. An attacker could 
possibly use this issue to cause GSS NTLMSSP to crash, resulting in 
a denial of service. (CVE-2023-25563, CVE-2023-25567)

Phil Turnbull discovered that GSS NTLMSSP did not properly initialize
memory when decoding UTF16 strings. An attacker could possibly use 
this issue to trigger an out-of-bounds write, resulting in a crash.
(CVE-2023-25564)

Phil Turnbull discovered that GSS NTLMSSP did not properly handle memory
cleanup. An attacker could possibly use this issue to cause an assertion
failure, resulting in a denial of service. (CVE-2023-25565)

Update instructions:

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

Ubuntu 22.04 LTS
  gss-ntlmssp                     0.7.0-4ubuntu0.22.04.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 20.04 LTS
  gss-ntlmssp                     0.7.0-4ubuntu0.20.04.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 18.04 LTS
  gss-ntlmssp                     0.7.0-4ubuntu0.18.04.1~esm1
                                  Available with Ubuntu Pro

Ubuntu 16.04 LTS
  gss-ntlmssp                     0.7.0-3~ubuntu0.16.04.1+esm1
                                  Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-7588-1
  CVE-2023-25563, CVE-2023-25564, CVE-2023-25565, CVE-2023-25567