// For flags

CVE-2025-6444

ServiceStack GetErrorResponse Improper Input Validation NTLM Relay Vulnerability

Severity Score

5.9
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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.

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.

*Credits: Piotr Bazydlo (@chudypb) of Trend Micro Zero Day Initiative
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
High
Authentication
None
Confidentiality
Complete
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2025-06-20 CVE Reserved
  • 2025-06-23 CVE Published
  • 2025-06-25 CVE Updated
  • 2025-07-01 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-20: Improper Input Validation
CAPEC
References (1)
URL Tag Source
https://www.zerodayinitiative.com/advisories/ZDI-25-415 X_research Advisory
URL Date SRC
URL Date SRC
URL Date SRC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
ServiceStack
Search vendor "ServiceStack"
 ServiceStack
Search vendor "ServiceStack" for product "ServiceStack"
 8.4.0
Search vendor "ServiceStack" for product "ServiceStack" and version "8.4.0"
en
Affected