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CWE-603

Use of Client-Side Authentication

21 CVEs Avg CVSS 8.3 MITRE
7
CRITICAL
11
HIGH
2
MEDIUM
0
LOW
2
POC
0
KEV

Monthly

CVE-2026-66305 Sep 08, 19:18 HIGH PATCH Exploit Unlikely This Week

Client-side authentication bypass in Microsoft Skype for Business Server enables a low-privileged network attacker to perform identity spoofing against other users on the platform. The flaw stems from CWE-603 (Use of Client-Side Authentication), where the server delegates trust to client-controlled data, allowing an authenticated user to forge session identity and corrupt integrity of communications. Three supported server product lines are affected with vendor patches now available; no public exploit or active exploitation has been identified at time of analysis.

NVD
CVSS 3.1
7.1
EPSS
0.3%
CVE-2026-76945 Aug 27, 21:35 HIGH CISA Act Now

Unauthorized administrative access in Ebyte NE2-D11 firmware is possible because the device delegates authentication state entirely to the client, performing no meaningful server-side token validation. An unauthenticated remote attacker can replay or forge authentication tokens to elevate access to administrative functionality without valid credentials. Reported via ICS-CERT advisory ICSA-26-237-06, this is an OT/ICS device vulnerability with no public exploit identified at time of analysis and no KEV listing.

Authentication Bypass Ebyte Ne2 D11 Firmware Ebyte
NVD GitHub
CVSS 4.0
8.7
EPSS
0.4%
CVE-2026-71187 Aug 27, 21:20 CRITICAL CISA Emergency

Authentication bypass in the Ebyte NE2-D11 serial-to-Ethernet gateway firmware lets unauthenticated remote attackers gain full administrative control by reproducing the device's client-side authentication logic. Because the login check runs in the client rather than being enforced server-side, an attacker can craft valid authentication requests without any credentials. No public exploit has been identified at time of analysis, but the flaw is trivially reproducible and carries a CVSS 4.0 base score of 9.3.

Authentication Bypass Ebyte Ne2 D11 Firmware Ebyte
NVD GitHub
CVSS 4.0
9.3
EPSS
0.5%
CVE-2026-42098 May 19, 12:59 HIGH This Week

Privilege escalation in Sparx Enterprise Architect 17.1 and earlier allows an authenticated low-privilege user to impersonate any other user, including administrators, by tampering with the client-side application (e.g., via a debugger). Because role-based access enforcement happens in the client rather than on the server (CWE-603), an attacker who has any valid login can gain full repository control. No public exploit identified at time of analysis, although technical write-ups are referenced.

Information Disclosure Enterprise Architect Sparx Systems
NVD VulDB
CVSS 4.0
8.7
EPSS
0.0%
CVE-2026-40551 Apr 28, 13:13 HIGH Monitor

Client-side authentication bypass in mpGabinet 23.12.19 and earlier allows local authenticated attackers to impersonate arbitrary users by patching the application binary. An attacker with legitimate low-privilege access to the system can manipulate the compiled application code to skip login verification entirely, gaining unauthorized access as any user including administrators. EPSS score not available for this 2026 CVE; no active exploitation or public POC confirmed at time of analysis.

Authentication Bypass Mpgabinet Binsoft
NVD
CVSS 4.0
8.4
EPSS
0.0%
CVE-2026-1363 Jan 23, 09:15 CRITICAL Act Now

IAQS and I6 systems by JNC have a client-side enforcement vulnerability allowing unauthenticated attackers to bypass security controls and access server functionality.

Information Disclosure
NVD
CVSS 3.1
9.8
EPSS
0.0%
CVE-2022-3218 Sep 19, 17:15 CRITICAL POC PATCH THREAT Act Now

Due to a reliance on client-side authentication, the WiFi Mouse (Mouse Server) from Necta LLC's authentication mechanism is trivially bypassed, which can result in remote code execution. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RCE Wifi Mouse Server
NVD GitHub Exploit-DB
CVSS 3.1
9.8
EPSS
73.5%
CVE-2026-8830 May 19, 06:04 Maven MEDIUM PATCH This Month

WebAuthn policy enforcement bypass in Red Hat Build of Keycloak allows low-privileged authenticated users to register credentials that violate administrator-configured realm security policies. The server-side processAction() method does not validate that newly registered WebAuthn credential parameters - such as public key algorithms - conform to the realm's defined WebAuthn policies, enabling a user to manipulate client-side JavaScript during the registration flow to submit non-compliant credential data. No public exploit has been identified at time of analysis; exploitation requires an authenticated session and is limited to integrity impact (policy bypass), with no direct confidentiality or availability consequence.

Authentication Bypass Red Hat Build Of Keycloak Red Hat
NVD VulDB
CVSS 3.1
4.3
EPSS
0.0%
CVE-2025-30042 Mar 02, 12:16 HIGH This Week

The CGM CLININET system provides smart card authentication; however, authentication is conducted locally on the client device, and, in reality, only the certificate number is used for access verification. [CVSS 7.8 HIGH]

Information Disclosure Clininet Cgm
NVD
CVSS 3.1
7.8
EPSS
0.0%
CVE-2025-64119 Jan 02, 22:15 Monitor

A vulnerability in Nuvation Battery Management System allows Authentication Bypass.This issue affects Battery Management System: through 2.3.9.

Authentication Bypass
NVD
EPSS
0.1%
EPSS 0% CVSS 7.1
HIGH PATCH Exploit Unlikely This Week

Client-side authentication bypass in Microsoft Skype for Business Server enables a low-privileged network attacker to perform identity spoofing against other users on the platform. The flaw stems from CWE-603 (Use of Client-Side Authentication), where the server delegates trust to client-controlled data, allowing an authenticated user to forge session identity and corrupt integrity of communications. Three supported server product lines are affected with vendor patches now available; no public exploit or active exploitation has been identified at time of analysis.

NVD
EPSS 0% CVSS 8.7
HIGH Act Now

Unauthorized administrative access in Ebyte NE2-D11 firmware is possible because the device delegates authentication state entirely to the client, performing no meaningful server-side token validation. An unauthenticated remote attacker can replay or forge authentication tokens to elevate access to administrative functionality without valid credentials. Reported via ICS-CERT advisory ICSA-26-237-06, this is an OT/ICS device vulnerability with no public exploit identified at time of analysis and no KEV listing.

Authentication Bypass Ebyte Ne2 D11 Firmware Ebyte
NVD GitHub
EPSS 1% CVSS 9.3
CRITICAL Emergency

Authentication bypass in the Ebyte NE2-D11 serial-to-Ethernet gateway firmware lets unauthenticated remote attackers gain full administrative control by reproducing the device's client-side authentication logic. Because the login check runs in the client rather than being enforced server-side, an attacker can craft valid authentication requests without any credentials. No public exploit has been identified at time of analysis, but the flaw is trivially reproducible and carries a CVSS 4.0 base score of 9.3.

Authentication Bypass Ebyte Ne2 D11 Firmware Ebyte
NVD GitHub
EPSS 0% CVSS 8.7
HIGH This Week

Privilege escalation in Sparx Enterprise Architect 17.1 and earlier allows an authenticated low-privilege user to impersonate any other user, including administrators, by tampering with the client-side application (e.g., via a debugger). Because role-based access enforcement happens in the client rather than on the server (CWE-603), an attacker who has any valid login can gain full repository control. No public exploit identified at time of analysis, although technical write-ups are referenced.

Information Disclosure Enterprise Architect Sparx Systems
NVD VulDB
EPSS 0% CVSS 8.4
HIGH Monitor

Client-side authentication bypass in mpGabinet 23.12.19 and earlier allows local authenticated attackers to impersonate arbitrary users by patching the application binary. An attacker with legitimate low-privilege access to the system can manipulate the compiled application code to skip login verification entirely, gaining unauthorized access as any user including administrators. EPSS score not available for this 2026 CVE; no active exploitation or public POC confirmed at time of analysis.

Authentication Bypass Mpgabinet Binsoft
NVD
EPSS 0% CVSS 9.8
CRITICAL Act Now

IAQS and I6 systems by JNC have a client-side enforcement vulnerability allowing unauthenticated attackers to bypass security controls and access server functionality.

Information Disclosure
NVD
EPSS 73% CVSS 9.8
CRITICAL POC PATCH THREAT Act Now

Due to a reliance on client-side authentication, the WiFi Mouse (Mouse Server) from Necta LLC's authentication mechanism is trivially bypassed, which can result in remote code execution. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RCE Wifi Mouse Server
NVD GitHub Exploit-DB
EPSS 0% CVSS 4.3
MEDIUM PATCH This Month

WebAuthn policy enforcement bypass in Red Hat Build of Keycloak allows low-privileged authenticated users to register credentials that violate administrator-configured realm security policies. The server-side processAction() method does not validate that newly registered WebAuthn credential parameters - such as public key algorithms - conform to the realm's defined WebAuthn policies, enabling a user to manipulate client-side JavaScript during the registration flow to submit non-compliant credential data. No public exploit has been identified at time of analysis; exploitation requires an authenticated session and is limited to integrity impact (policy bypass), with no direct confidentiality or availability consequence.

Authentication Bypass Red Hat Build Of Keycloak Red Hat
NVD VulDB
EPSS 0% CVSS 7.8
HIGH This Week

The CGM CLININET system provides smart card authentication; however, authentication is conducted locally on the client device, and, in reality, only the certificate number is used for access verification. [CVSS 7.8 HIGH]

Information Disclosure Clininet Cgm
NVD
EPSS 0%
Monitor

A vulnerability in Nuvation Battery Management System allows Authentication Bypass.This issue affects Battery Management System: through 2.3.9.

Authentication Bypass
NVD

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