CVE-2026-2676: GoogTech sms-ssm Auth Bypass Vulnerability

CVE-2026-2676 Overview

A weakness has been identified in GoogTech sms-ssm up to commit e8534c766fd13f5f94c01dab475d75f286918a8d. Affected by this issue is the function preHandle of the file LoginInterceptor.java of the component API Interface. Executing a manipulation can lead to improper authorization. The attack may be performed remotely. The exploit has been made available to the public and could be used for attacks. This product utilizes a rolling release system for continuous delivery, and as such, version information for affected or updated releases is not disclosed.

Critical Impact
This improper authorization vulnerability in the LoginInterceptor.java component allows remote attackers to bypass authentication controls via the API Interface, potentially gaining unauthorized access to protected resources and functionality.

Affected Products

GoogTech sms-ssm (up to commit e8534c766fd13f5f94c01dab475d75f286918a8d)
sms-ssm API Interface component
LoginInterceptor.java authentication handler

Discovery Timeline

2026-02-18 - CVE-2026-2676 published to NVD
2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-2676

Vulnerability Analysis

This vulnerability represents an improper authorization flaw (CWE-266: Incorrect Privilege Assignment) within the GoogTech sms-ssm application. The weakness resides specifically in the preHandle function within LoginInterceptor.java, which is responsible for intercepting and validating requests to the API Interface before they are processed.

The core issue stems from inadequate authorization checks in the login interceptor logic. When requests are made to protected API endpoints, the preHandle function fails to properly validate user privileges or session states, allowing attackers to manipulate requests in ways that bypass the intended access controls.

The network-accessible nature of this vulnerability means that any attacker with network access to the application can potentially exploit this flaw without requiring prior authentication. The public availability of exploit information increases the risk profile for organizations running affected versions.

Root Cause

The root cause of CVE-2026-2676 lies in the preHandle method implementation within LoginInterceptor.java. This interceptor component is designed to act as a gatekeeper for API requests, verifying that users are properly authenticated and authorized before allowing access to protected resources.

The vulnerability arises from incorrect privilege assignment logic in this interceptor. Rather than properly validating user credentials and authorization levels against the requested resource, the function contains flaws that allow certain manipulated requests to pass through without adequate verification. This is classified under CWE-266, which specifically addresses scenarios where privileges are incorrectly assigned to actors in the system.

Attack Vector

The attack vector for this vulnerability is network-based, allowing remote exploitation without physical access to the target system. An attacker can exploit this vulnerability by:

Identifying an exposed sms-ssm API endpoint
Crafting manipulated HTTP requests targeting the API Interface
Bypassing the flawed preHandle authorization checks in LoginInterceptor.java
Gaining unauthorized access to protected functionality or data

The vulnerability allows low-privileged users to potentially access resources or perform actions that should require higher privileges. Due to the rolling release nature of the sms-ssm project, pinpointing specific vulnerable versions is challenging. Technical details regarding the specific exploitation method are documented in the GitHub Issue #27 on SMS-SSM repository issue tracker.

Detection Methods for CVE-2026-2676

Indicators of Compromise

Unusual API access patterns from unauthenticated or low-privileged sessions
Requests to protected API endpoints that bypass normal authentication flows
Anomalous activity in LoginInterceptor.java logs showing authorization failures followed by successful access
Multiple rapid requests to API Interface endpoints from single sources

Detection Strategies

Implement API request logging and analyze for authorization bypass patterns
Monitor for requests that access protected resources without proper session tokens
Deploy Web Application Firewalls (WAF) with rules to detect authorization manipulation attempts
Review application logs for preHandle function execution anomalies

Monitoring Recommendations

Enable verbose logging for the LoginInterceptor component to capture all authorization decisions
Set up alerts for failed authentication attempts followed by successful resource access from the same source
Monitor API endpoint access patterns for deviation from normal user behavior
Implement real-time monitoring for the sms-ssm API Interface component

How to Mitigate CVE-2026-2676

Immediate Actions Required

Review and audit the LoginInterceptor.java implementation for proper authorization logic
Restrict network access to the sms-ssm API Interface to trusted sources only
Implement additional authorization checks at the API endpoint level as defense-in-depth
Monitor for exploitation attempts while applying remediation

Patch Information

The sms-ssm project uses a rolling release model, which means traditional versioned patches are not released. Organizations should pull the latest commits from the GitHub Repository for SMS-SSM and verify that the preHandle function in LoginInterceptor.java has been updated to properly validate authorization. Track the GitHub Issue #27 on SMS-SSM for updates on the fix status and any official guidance from the maintainers.

Workarounds

Implement a reverse proxy or API gateway with additional authorization validation in front of the sms-ssm application
Add network-level access controls to limit exposure of the API Interface to trusted IP ranges only
Deploy a Web Application Firewall with custom rules to validate authorization headers and tokens
Consider disabling public access to vulnerable API endpoints until a fix is applied

bash

# Example: Restrict API access using iptables (Linux)
# Allow only trusted IP range to access the sms-ssm API port
iptables -A INPUT -p tcp --dport 8080 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP