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%.

Which versions of IIS are affected by CVE-2026-26333?

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.

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.

IIS CVE-2026-26333

CRITICAL

Missing Authentication for Critical Function (CWE-306)

2026-02-13 disclosure@vulncheck.com

IIS .NET RCE 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 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.

AnalysisAI

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