CVE-2026-39906: Unisys WebPerfect Image Suite versions 3.0.3960.22810 and 3.0.3960.22604 expose a deprecated .NET Remoting TCP

This week

CRITICAL 10.0REMOTEDOWNGRADE

CVE-2026-39906 is a critical-severity flaw (CVSS 10.0) affecting webperfect image suite. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 con

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-441
Published	2026-04-14
Last modified	2026-07-24

Publisher (CNA): VulnCheck · Vendor: unisys

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-14 22:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

unisys webperfect image suite DOWNGRADE

Affected: 3.0.3960.22604 · 3.0.3960.22810

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.3960.22604

1. Check installed version

apt-cache policy webperfect-image-suite || rpm -q webperfect-image-suite || webperfect-image-suite --version

2. No fixed release: DOWNGRADE to a release before 3.0.3960.22604 (Debian / Ubuntu)

apt-cache madison webperfect-image-suite sudo apt install webperfect-image-suite=<VERSION_BEFORE_3.0.3960.22604> sudo apt-mark hold webperfect-image-suite

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list webperfect-image-suite sudo dnf downgrade webperfect-image-suite-<VERSION_BEFORE_3.0.3960.22604> sudo dnf versionlock add webperfect-image-suite

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · icecat · FIXED · 153.6.0-2.rh1.fc46 · FEDORA-2026-25e05b5320 · source

sudo dnf upgrade --advisory=FEDORA-2026-25e05b5320

Fedora ELN · edk2 · FIXED · 20260812-14.eln159 · FEDORA-2026-8850ef9153 · source

sudo dnf upgrade --advisory=FEDORA-2026-8850ef9153

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: gist.github.com/VAMorales/be3e4ed472c51794493c1256cce16129

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-2026-39906?

webperfect image suite: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-39906 being exploited?

CVE-2026-39906 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-2026-39906 affect?

CVE-2026-39906 affects webperfect image suite. Severity is critical (CVSS 10.0). 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 t

How urgent is CVE-2026-39906?

Priority 61/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

Windows vulnerabilities

Related CVEs

CVE-2026-39907 CRITICAL 10.0 DOWNGRADE Unisys WebPerfect Image Suite versions 3.0.3960.22810 and 3.0.3960.22604 expose an unauthenticated WCF SOAP en

References

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