What is the CVSS score of CVE-2026-26335?

CVE-2026-26335 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.1%.

Which versions of IIS are affected by CVE-2026-26335?

Calero VeraSMART installations are vulnerable to critical cryptographic key compromise due to hardcoded static encryption keys in configuration files.

Is there a public PoC exploit available for CVE-2026-26335?

Yes, a public proof-of-concept exploit is available for CVE-2026-26335. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-26335?

Within 24 hours: Identify and inventory all VeraSMART deployments and versions in your environment; isolate affected systems from untrusted networks if possible. Within 7 days: Implement network segmentation to restrict access to VeraSMART web applications; enable detailed logging and monitoring for suspicious authentication and data access patterns; begin testing upgrade path to VeraSMART 2022 R1 or later in a non-production environment. Within 30 days: Complete upgrade of all VeraSMART instances to version 2022 R1 or later; rotate all credentials and session tokens associated with affected systems; conduct forensic analysis for signs of exploitation.

IIS CVE-2026-26335

CRITICAL

Use of Hard-coded Cryptographic Key (CWE-321)

2026-02-13 disclosure@vulncheck.com

IIS .NET RCE Deserialization Verasmart

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:02 vuln.today

CVE Published

Feb 13, 2026 - 21:16 nvd

CRITICAL 9.8

DescriptionCVE.org

Calero VeraSMART versions prior to 2022 R1 use static ASP.NET/IIS machineKey values configured for the VeraSMART web application and stored in C:\\Program Files (x86)\\Veramark\\VeraSMART\\WebRoot\\web.config. An attacker who obtains these keys can craft a valid ASP.NET ViewState payload that passes integrity validation and is accepted by the application, resulting in server-side deserialization and remote code execution in the context of the IIS application.

AnalysisAI

Static ASP.NET machineKey in Calero VeraSMART before 2022 R1. Hardcoded key enables ViewState deserialization attacks and cookie forgery.

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Obtain static machineKey from web.config

Delivery

Craft malicious ASP.NET ViewState payload

Exploit

Submit payload to application

Execution

Trigger unsafe deserialization

Impact

Execute arbitrary code as IIS user

Access

Obtain static machineKey from web.config

Delivery

Craft malicious ASP.NET ViewState payload

Exploit

Submit payload to application

Execution

Trigger unsafe deserialization

Impact

Execute arbitrary code as IIS user

Vulnerability AssessmentAI

Exploitation	Static machineKey values in C:\Program Files (x86)\Veramark\VeraSMART\WebRoot\web.config must be accessible to attacker. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	CVSS 9.8. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	Attacker uses known machineKey to craft malicious ViewState payload, achieving RCE through deserialization.
Remediation	Update to 2022 R1. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Identify and inventory all VeraSMART deployments and versions in your environment; isolate affected systems from untrusted networks if possible. …

Threat intelligence, references, and detailed analysis are available after sign-in.

CVE-2026-26335 vulnerability details – vuln.today

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IIS CVE-2026-26335

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

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Attack ChainAIDerived

Vulnerability AssessmentAI

Recommended ActionAI

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External POC / Exploit Code