CVE-2026-39906

HighPublic PoC

Published: 14 April 2026

Published

14 April 2026

Modified

06 May 2026

KEV Added

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Patch

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CVSS Score v4 7.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Score 0.0069 47.9th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-39906 is a high-severity Confused Deputy (CWE-441) vulnerability in Unisys Webperfect Image Suite. Its CVSS base score is 7.0 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 47.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-22724

Vulnerability details

Unisys WebPerfect Image Suite versions 3.0.3960.22810 and 3.0.3960.22604 expose a deprecated .NET Remoting TCP channel that allows remote unauthenticated attackers to leak NTLMv2 machine-account hashes by supplying a Windows UNC path as a target file argument through object-unmarshalling techniques. Attackers…

can capture the leaked NTLMv2 hash and relay it to other hosts to achieve privilege escalation or lateral movement depending on network configuration and patch level.

CWE(s): CWE-441

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1187 Forced Authentication Credential Access

Adversaries may gather credential material by invoking or forcing a user to automatically provide authentication information through a mechanism in which they can intercept.

attack.mitre.org →

Why these techniques?

The exposed .NET Remoting channel enables remote unauthenticated exploitation of a public-facing application (T1190). Supplying a UNC path directly forces NTLM authentication to an attacker server (T1187), enabling hash capture and relay.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0