What is the CVSS score of CVE-2026-26333?

CVE-2026-26333 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: 0.2%.

How to fix or mitigate CVE-2026-26333?

Within 24 hours: Identify and inventory all Calero VeraSMART deployments, document versions, and assess network exposure of port 8001. Within 7 days: Implement network segmentation to restrict access to port 8001 (TCP) to trusted networks only, deploy WAF rules to block .NET Remoting requests, and disable the HTTP remoting service if operationally feasible. Within 30 days: Plan and execute upgrade to VeraSMART 2022 R1 or later, or migrate to alternative solutions if upgrade timeline exceeds risk tolerance.

Verasmart CVE-2026-26333

CRITICAL

Missing Authentication for Critical Function (CWE-306)

2026-02-13 disclosure@vulncheck.com

RCE .NET IIS Verasmart Calero

9.8

CVSS 3.1 · NVD

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Connect to exposed .NET Remoting service on TCP 8001
Delivery

Invoke EndeavorServer.rem or RemoteFileReceiver.rem endpoint
Exploit

Instantiate WebClient through unsafe formatter
Execution

Read arbitrary files including web.config
Impact

Exfiltrate IIS machineKey credentials

Vulnerability Assessment

Weakness	CWE CWE-306 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication required for critical functions MITRE ATT&CK 1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	Calero VeraSMART versions prior to 2022 R1 with unauthenticated .NET Remoting HTTP service enabled on TCP port 8001, publishing default ObjectURIs (EndeavorServer.rem, RemoteFileReceiver.rem) with TypeFilterLevel set to Full allowing SOAP and binary formatters.
Impact	CVSS 9.8. .NET Remoting deserialization is a well-understood attack vector with public tooling.
Exploit ScenarioDerived	Attacker connects to TCP 8001, exploits .NET Remoting deserialization for RCE.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.

No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Unauthenticated .NET Remoting endpoint in Calero VeraSMART before 2022 R1. TCP port 8001 exposes default Object URIs enabling deserialization attacks. EPSS 0.17%.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:02 CVSS 9.8

Unauthenticated .NET Remoting in Calero VeraSMART.

RemediationAI

Update to 2022 R1. Block port 8001 access.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-306 in Calero VeraSMART telecom expense management. .NET Remoting over TCP without auth.

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Exploit and PoC references, threat intelligence from 22 sources

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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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

Calero VeraSMART versions prior to 2022 R1 expose an unauthenticated .NET Remoting HTTP service on TCP port 8001. The service publishes default ObjectURIs (including EndeavorServer.rem and RemoteFileReceiver.rem) and permits the use of SOAP and binary formatters with TypeFilterLevel set to Full. An unauthenticated remote attacker can invoke the exposed remoting endpoints to perform arbitrary file read and write operations via the WebClient class. This allows retrieval of sensitive files such as WebRoot\\web.config, which may disclose IIS machineKey validation and decryption keys. An attacker can use these keys to generate a malicious ASP.NET ViewState payload and achieve remote code execution within the IIS application context. Additionally, supplying a UNC path can trigger outbound SMB authentication from the service account, potentially exposing NTLMv2 hashes for relay or offline cracking.

Executive ViewAI

Why It Matters

Calero VeraSMART installations prior to version 2022 R1 contain a critical vulnerability allowing unauthenticated remote attackers to read and write arbitrary files on affected servers. Organizations running vulnerable versions face immediate risk of data theft, system compromise, and operational disruption with no vendor patch currently available.

Business Impact: Severe

Compensating Controls

Network segmentation restricting port 8001 access to trusted internal networks only; disable the HTTP remoting service via application configuration if functionality permits; Web Application Firewall rules blocking .NET Remoting endpoints (EndeavorServer.rem, RemoteFileReceiver.rem); disable SOAP and binary formatter support if possible; implement host-based firewall rules; continuous monitoring for unauthorized file access patterns.

Threat Intelligence Overview

EPSS Score

0.2%

Top 62% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC No

EPSS 0.2%

Patch available No

Active threat No

Deciding rule

CRITICAL severity

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.