How severe is CVE-2025-6444?

CVE-2025-6444 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-6444 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6444?

CVE-2025-6444 affects Servicestack. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-6444?

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

Does CVE-2025-6444 have an EU (EUVD) identifier?

Yes. CVE-2025-6444 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19133.

When was CVE-2025-6444 published?

CVE-2025-6444 was published on 2025-06-25 and last updated on 2026-06-17.

CVE-2025-6444

CVE-2025-6444 is a medium-severity vulnerability in Servicestack with a CVSS 3.x base score of 5.9. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-19133
Weakness: CWE-20
Affected product: Servicestack
Published: 2025-06-25
Last modified: 2026-06-17

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.

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 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-6444 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6444?: CVE-2025-6444 affects Servicestack. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-6444?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-6444 have an EU (EUVD) identifier?: Yes. CVE-2025-6444 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19133.
When was CVE-2025-6444 published?: CVE-2025-6444 was published on 2025-06-25 and last updated on 2026-06-17.

References

https://www.zerodayinitiative.com/advisories/ZDI-25-415/

Affected products (1)

cpe:2.3:a:servicestack:servicestack:*:*:*:*:*:*:*:*

More vulnerabilities in Servicestack

CVE-2025-6445 — High (CVSS 8.1): ServiceStack FindType Directory Traversal Remote Code Execution Vulnerability. This vulnerability allows remote…
CVE-2019-1010199 — Medium (CVSS 6.1): ServiceStack ServiceStack Framework 4.5.14 is affected by: Cross Site Scripting (XSS). The impact is: JavaScrpit is…
CVE-2020-28042 — Medium (CVSS 5.3): ServiceStack before 5.9.2 mishandles JWT signature verification unless an application has a custom ValidateToken…

All CVEs affecting Servicestack →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →