CVE-2017-20235

CriticalPublic PoC

Published: 03 April 2026

Published

03 April 2026

Modified

22 April 2026

KEV Added

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Patch

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CVSS Score 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Score 0.0009 25.1th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2017-20235 is a critical-severity Improper Authentication (CWE-287) vulnerability in Prosoft-Technology Icx35-Hwc Firmware. Its CVSS base score is 9.1 (Critical).

Operationally, ranked at the 25.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and IA-2 (Identification and Authentication (Organizational Users)).

Threat & Defense at a Glance

What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Flaw remediation requires timely patching of the vulnerable firmware to eliminate the authentication bypass in the web user interface.

IA-2 Identification and Authentication (Organizational Users) good match

prevent

Identification and authentication for organizational users ensures valid credentials are required before granting administrative access via the web interface.

AC-3 Access Enforcement good match

prevent

Access enforcement mechanisms prevent unauthenticated attackers from reaching administrative functions despite the bypass vulnerability.

NVD Description

ProSoft Technology ICX35-HWC version 1.3 and prior cellular gateways contain an authentication bypass vulnerability in the web user interface that allows unauthenticated attackers to gain access to administrative functions without valid credentials. Attackers can bypass the authentication mechanism in affected…

firmware versions to obtain full administrative access to device configuration and settings.

Deeper analysisAI

CVE-2017-20235 is an authentication bypass vulnerability (CWE-287) in the web user interface of ProSoft Technology ICX35-HWC cellular gateways running version 1.3 and prior. It enables unauthenticated attackers to access administrative functions without valid credentials by bypassing the authentication mechanism in affected firmware versions. The vulnerability carries a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N), indicating high confidentiality and integrity impacts with no availability disruption.

Unauthenticated remote attackers with network access to the device's web interface can exploit this issue to gain full administrative privileges over the gateway. Successful exploitation allows attackers to modify device configuration and settings arbitrarily, potentially enabling unauthorized network access, data manipulation, or use of the gateway as a pivot for further attacks.

Mitigation guidance is detailed in the Belden Security Bulletin BSECV-2017-09 (https://assets.belden.com/m/1281cac2c9e90abf/original/Security-Bulletin-Authentication-Security-ProSoft-ICX35-BSECV-2017-09.pdf) and the VulnCheck advisory (https://www.vulncheck.com/advisories/prosoft-technology-icx35-hwc-authentication-bypass). Security practitioners should review these resources for firmware updates, patching procedures, and any recommended workarounds.