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CVE-2025-6444

MEDIUMCVSS 5.9/10EPSS 0.39%

Last modified

CVE-2025-6444 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. ServiceStack GetErrorResponse Improper Input Validation NTLM Relay Vulnerability. This vulnerability allows remote attackers to relay NTLM credentials on affected installations of ServiceStack. EPSS estimates a 0.39% chance of exploitation in the next 30 days.

Description

ServiceStack GetErrorResponse Improper Input Validation NTLM Relay Vulnerability. This vulnerability allows remote attackers to relay NTLM credentials on affected installations of ServiceStack. Interaction with this library is required to exploit this vulnerability but attack vectors may vary depending on the implementation. The specific flaw exists within the implementation of the GetErrorResponse method. The issue results from the lack of proper validation of user-supplied data, which can result in a type confusion condition. An attacker can leverage this vulnerability to relay NTLM credentials in the context of the current user. Was ZDI-CAN-25834.

Metrics

CVSS 3.1
5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability
0.39%

31.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
ServicestackServicestack< 8.6

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2025-6444?
ServiceStack GetErrorResponse Improper Input Validation NTLM Relay Vulnerability. This vulnerability allows remote attackers to relay NTLM credentials on affected installations of ServiceStack. Interaction with this library is required to exploit this vulnerability but attack vectors may vary depending on the implementation. The specific flaw exists within the implementation of the GetErrorResponse method. The issue results from the lack of proper validation of user-supplied data, which can result in a type confusion condition. An attacker can leverage this vulnerability to relay NTLM credentials in the context of the current user. Was ZDI-CAN-25834.
How severe is CVE-2025-6444?
CVE-2025-6444 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.39% probability of exploitation in the next 30 days.
How do I fix CVE-2025-6444?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-6444?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST