Improper input validation in ServiceStack
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| ServiceStack | ServiceStack | 8.4.0 | — | No fix listed | CNA |
- ServiceStack VendorServiceStack Affected 8.4.0 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:servicestack:servicestack:*:*:*:*:*:*:*:* | before 8.6 | Vulnerable | ServiceStack |
- cpe:2.3:a:servicestack:servicestack:*:*:*:*:*:*:*:* Versions before 8.6 Vulnerable ·ServiceStack
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2025-6444
- 2026-10-03 Alias added: GHSA-2cp7-3mjq-769q
References
Advisory 1
More Servicestack vulnerabilities
- TI-2025-05846 Path traversal in ServiceStack CVSS 3.1HIGH 8.1
- TI-2020-17068 ServiceStack before 5.9.2 mishandles JWT signature verification unless an application has… CVSS 3.1MEDIUM 5.3
- TI-2019-16015 Cross-site scripting in ServiceStack Framework CVSS 3.0MEDIUM 6.1
Sources
- CVE-2025-6444 · CVE Program
- CVE-2025-6444 · NVD
- FIRST EPSS
- GHSA-2cp7-3mjq-769q · GitHub Advisory Database · CC BY 4.0
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