PatchTheCVECVE-2023-25564: GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication
CVE-2023-25564 is a medium-severity flaw (CVSS 6.5) affecting gss-ntlmssp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, memory corruption can be triggered when decoding UTF16 strings. The variable `outlen` was not initialized and could cause writing a zero to an arbitrary place in memory if `ntlm_str_convert()` were to fail, which would leave `outlen` uninitialized. This can lead to a denial of service if the write hits unmapped memory or randomly c
Why this priority
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.9% (top 20%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2023-02-14 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2023-25564?
gss-ntlmssp: upgrade to 1.2.0. Exact commands for each OS are on this page.
Is CVE-2023-25564 being exploited?
CVE-2023-25564 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2023-25564 affect?
CVE-2023-25564 affects gss-ntlmssp. Severity is medium (CVSS 6.5). GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, memory corruption can be triggered when decoding UTF16 strings. The variable `outlen` was not initialized and could cause w
How urgent is CVE-2023-25564?
Priority 48/100. Remotely exploitable, no login, no user action
Related CVEs
- CVE-2023-25567 HIGH 7.5 UPGRADE GSS-NTLMSSP, a mechglue plugin for the GSSAPI library that implements NTLM authentication, has an out-of-bound
- CVE-2023-25566 HIGH 7.5 UPGRADE GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication
- CVE-2023-25565 HIGH 7.5 UPGRADE GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication
- CVE-2023-25563 MEDIUM 5.9 UPGRADE GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication