CVE-2025-6444: ServiceStack GetErrorResponse Improper Input Validation NTLM Relay Vulnerability

Q: How do I fix CVE-2025-6444?

servicestack: upgrade to 8.6. Exact commands for each OS are on this page.

Q: Is CVE-2025-6444 being exploited?

CVE-2025-6444 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-6444 affect?

CVE-2025-6444 affects servicestack. Severity is medium (CVSS 5.9). 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 e

Q: How urgent is CVE-2025-6444?

Priority 36/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.9REMOTEUPGRADE

CVE-2025-6444 is a medium-severity flaw (CVSS 5.9) affecting servicestack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 prop

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-20
Published	2025-06-25
Last modified	2026-06-17

Publisher (CNA): Zero Day Initiative · Vendor: servicestack

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-06-25 18:15 UTCPublished CVE record published
2026-06-17 10:01 UTCUpdated Record last modified

servicestack servicestack UPGRADE

Affected: < 8.6

Fixed in: 8.6

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy servicestack || rpm -q servicestack || servicestack --version

2. UPGRADE to 8.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade servicestack

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade servicestack

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-6444?

servicestack: upgrade to 8.6. Exact commands for each OS are on this page.

Is CVE-2025-6444 being exploited?

CVE-2025-6444 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-6444 affect?

CVE-2025-6444 affects servicestack. Severity is medium (CVSS 5.9). 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 e

How urgent is CVE-2025-6444?

Priority 36/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-6445 HIGH 8.1 UPGRADE ServiceStack FindType Directory Traversal Remote Code Execution Vulnerability

References

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