CVE-2026-25660: Ericsson Codechecker Auth Bypass Flaw

CVE-2026-25660 Overview

CVE-2026-25660 is an Authentication Bypass vulnerability affecting Ericsson CodeChecker, an analyzer tooling, defect database, and viewer extension for the Clang Static Analyzer and Clang Tidy. The vulnerability allows attackers to bypass authentication mechanisms when the URL ends with specific patterns combined with certain function calls. This bypass enables unauthorized users to assign arbitrary permissions to any existing user within the CodeChecker system, potentially leading to complete compromise of the application's access control.

Critical Impact

This authentication bypass vulnerability allows unauthenticated attackers to escalate privileges and assign arbitrary permissions to any user in CodeChecker, potentially compromising the entire defect database and analysis infrastructure.

Affected Products

• Ericsson CodeChecker through version 6.27.3

Discovery Timeline

• 2026-04-24 - CVE-2026-25660 published to NVD
• 2026-04-27 - Last updated in NVD database

Technical Details for CVE-2026-25660

Vulnerability Analysis

This vulnerability is classified as CWE-290 (Authentication Bypass by Spoofing), where the application fails to properly validate authentication for certain URL patterns. The flaw exists in how CodeChecker processes requests where the URL terminates with specific authentication-related strings. When exploited, an attacker can craft malicious requests that circumvent the normal authentication flow entirely.

The network-based attack vector requires no user interaction or special privileges, making this vulnerability particularly dangerous in environments where CodeChecker is exposed to untrusted networks. Successful exploitation grants attackers the ability to manipulate user permissions, effectively providing administrative control over the defect tracking system.

Root Cause

The root cause stems from improper URL validation in the authentication middleware. CodeChecker's request routing logic contains a flaw where URLs ending with certain authentication-related function call patterns are not properly validated against the authentication framework. This allows attackers to construct URLs that match the pattern while bypassing standard authentication checks, enabling unauthorized access to permission assignment functionality.

Attack Vector

The attack is conducted remotely over the network without requiring any authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying a CodeChecker instance accessible over the network
2. Crafting HTTP requests with specially formatted URLs that end with authentication-triggering patterns
3. Sending requests that bypass the authentication layer
4. Assigning arbitrary permissions to existing user accounts, including elevating their own account to administrative privileges

The vulnerability allows complete circumvention of access controls, enabling attackers to modify the permission structure of the entire CodeChecker deployment. This could lead to unauthorized access to sensitive defect data, code analysis results, and the ability to manipulate or delete security findings.

Detection Methods for CVE-2026-25660

Indicators of Compromise

• Unusual permission changes in CodeChecker user accounts, especially unexpected privilege escalations
• Authentication logs showing successful permission modifications without corresponding valid authentication events
• HTTP access logs containing malformed or suspicious URL patterns ending with authentication-related strings
• Unexpected administrative actions performed by non-administrative accounts

Detection Strategies

• Monitor CodeChecker access logs for unusual URL patterns, particularly requests with authentication keywords at the end of the URL path
• Implement Web Application Firewall (WAF) rules to detect and block malformed authentication requests
• Review user permission audit logs for unauthorized changes to user roles and permissions
• Configure alerting for permission modifications outside of normal administrative workflows

Monitoring Recommendations

• Enable comprehensive logging for all authentication and authorization events in CodeChecker
• Set up automated alerts for any permission changes to critical user accounts
• Implement network-level monitoring to detect anomalous traffic patterns to CodeChecker endpoints
• Regularly audit user permissions to identify unauthorized privilege escalations

How to Mitigate CVE-2026-25660

Immediate Actions Required

• Upgrade Ericsson CodeChecker to a version newer than 6.27.3 that contains the security fix
• Restrict network access to CodeChecker instances using firewall rules to limit exposure to trusted networks only
• Audit all current user permissions to identify and remediate any unauthorized privilege escalations
• Review authentication logs for evidence of prior exploitation attempts

Patch Information

Ericsson has released a security advisory addressing this vulnerability. Organizations should consult the GitHub Security Advisory GHSA-4v9x-cqc5-j645 for detailed patching instructions and upgrade to the latest available version of CodeChecker that resolves this authentication bypass.

Workarounds

• Place CodeChecker behind a reverse proxy with additional authentication requirements until patching is possible
• Implement network segmentation to restrict access to CodeChecker instances to only authorized internal networks
• Enable additional logging and monitoring to detect potential exploitation attempts
• Consider temporarily disabling public network access to CodeChecker if a patch cannot be immediately applied