CVE-2025-6444
low-risk
Published 2025-06-25
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.
Do I need to act?
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0.07% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.9/10
Medium
NETWORK
/ HIGH complexity
Affected Products (1)
Servicestack
Affected Vendors
References (1)
Third Party Advisory
https://www.zerodayinitiative.com/advisories/ZDI-25-415/
23
/ 100
low-risk
Severity
18/34 · Moderate
Exploitability
0/34 · Minimal
Exposure
5/34 · Minimal