How severe is CVE-2023-25564?

CVE-2023-25564 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2023-25564 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-25564?

CVE-2023-25564 affects Gss-ntlmssp Project Gss-ntlmssp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2023-25564?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-25564 published?

CVE-2023-25564 was published on 2023-02-14 and last updated on 2026-06-17.

CVE-2023-25564

CVE-2023-25564 is a medium-severity vulnerability in Gss-ntlmssp Project Gss-ntlmssp with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Gss-ntlmssp Project Gss-ntlmssp
Published: 2023-02-14
Last modified: 2026-06-17

Description

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 corrupts a byte in the application memory space. This vulnerability can trigger an out-of-bounds write, leading to memory corruption. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point. This issue is fixed in version 1.2.0.

Frequently asked questions

What is CVE-2023-25564?: 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 corrupts a byte in the application memory space. This vulnerability can trigger an out-of-bounds write, leading to memory corruption. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point. This issue is fixed in version 1.2.0.
How severe is CVE-2023-25564?: CVE-2023-25564 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2023-25564 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-25564?: CVE-2023-25564 affects Gss-ntlmssp Project Gss-ntlmssp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-25564?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-25564 published?: CVE-2023-25564 was published on 2023-02-14 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gss-ntlmssp_project:gss-ntlmssp:*:*:*:*:*:*:*:*

More vulnerabilities in Gss-ntlmssp Project Gss-ntlmssp

CVE-2023-25567 — High (CVSS 7.5): GSS-NTLMSSP, a mechglue plugin for the GSSAPI library that implements NTLM authentication, has an out-of-bounds read…
CVE-2023-25566 — High (CVSS 7.5): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, a…
CVE-2023-25565 — High (CVSS 7.5): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, an…
CVE-2023-25563 — Medium (CVSS 5.9): GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0,…

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