Skip to main content
Mallory
Critical

Unauthenticated ViewState Deserialization RCE in Digital Knowledge KnowledgeDeliver

IdentifiersCVE-2026-5426CWE-798

CVE-2026-5426 is an unauthenticated remote code execution vulnerability in Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026. The root cause is the use of hard-coded/shared ASP.NET machineKey values in a standardized vendor-supplied web.config configuration. Because ASP.NET uses machineKey material to sign and encrypt ViewState data, an attacker who knows the shared key can forge a malicious __VIEWSTATE payload that passes validation. The application then deserializes attacker-controlled ViewState data, resulting in code execution in the IIS/ASP.NET worker process context. Reporting indicates the flaw was exploited in the wild as a zero-day to deploy the Godzilla/BLUEBEAM web shell and follow-on payloads.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows unauthenticated attackers to achieve remote code execution against exposed KnowledgeDeliver servers. Observed post-exploitation activity included deployment of the Godzilla/BLUEBEAM in-memory web shell, execution of arbitrary commands, modification of file permissions, tampering with legitimate JavaScript files, and delivery of follow-on malware including Cobalt Strike Beacon. Because the machineKey was shared across deployments, compromise of one instance could enable attacks against other internet-facing KnowledgeDeliver installations using the same key material.

Mitigation

If you can’t patch tonight, do this now.

If immediate remediation is not possible, restrict access to the KnowledgeDeliver application to trusted IP ranges or place it behind access controls to reduce internet exposure. Monitor for ASP.NET ViewState anomalies, including Application log Event ID 1316, suspicious requests carrying forged __VIEWSTATE data, and child processes such as cmd.exe or powershell.exe launched by w3wp.exe. Hunt for indicators associated with BLUEBEAM/Godzilla, altered JavaScript assets, unauthorized permission changes, and known malicious payloads. These measures reduce exposure but do not eliminate the underlying risk while shared machine keys remain in use.

Remediation

Patch, then assume compromise.

Upgrade or reconfigure affected Digital Knowledge KnowledgeDeliver deployments so they no longer use the vendor-supplied hard-coded/shared ASP.NET machineKey values. Deploy unique, cryptographically strong machineKey values per installation, especially for systems deployed prior to February 24, 2026. Apply the vendor patch/fixed release issued after February 24, 2026, rotate any exposed machine keys, and review the environment for post-compromise artifacts such as modified web files, malicious JavaScript, web shells, and suspicious child processes spawned by w3wp.exe.
PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Digital KnowledgeKnowledgedeliverapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

43 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware10

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity39

Community discussion across Reddit, Mastodon, and other social sources.