CVE-2026-16199: GoClaw Auth Bypass Vulnerability

CVE-2026-16199 Overview

CVE-2026-16199 is an improper authorization vulnerability [CWE-266] in nextlevelbuilder GoClaw versions up to 3.13.3-beta.3. The flaw resides in the ExecTool.Execute function within goclaw/internal/tools/credentialed_exec.go. An authenticated attacker can manipulate the function remotely to trigger improper authorization checks, resulting in limited impact to confidentiality, integrity, and availability.

A public exploit has been disclosed, increasing the likelihood of opportunistic exploitation attempts against exposed GoClaw deployments.

Critical Impact
An attacker with low privileges can remotely exploit the ExecTool.Execute function to bypass authorization controls in GoClaw, gaining unauthorized access to protected tool execution paths.

Affected Products

nextlevelbuilder GoClaw up to 3.13.3-beta.3
Component: goclaw/internal/tools/credentialed_exec.go
Function: ExecTool.Execute

Discovery Timeline

2026-07-19 - CVE-2026-16199 published to NVD
2026-07-20 - Last updated in NVD database

Technical Details for CVE-2026-16199

Vulnerability Analysis

The vulnerability is classified as improper authorization [CWE-266], meaning that GoClaw performs privilege assignment or checks incorrectly when executing credentialed tools. The ExecTool.Execute function in credentialed_exec.go fails to sufficiently validate whether the requesting principal is authorized for the requested action.

An authenticated user with minimal privileges can invoke the function over the network and manipulate its inputs to reach code paths that should be restricted. Because the impact scope covers confidentiality, integrity, and availability at a low level, exploitation does not provide full system compromise but does permit unauthorized action execution within the application context.

The attack vector is network-based, requires low attack complexity, and needs only low-level privileges with no user interaction, making it accessible to any authenticated user of the application.

Root Cause

The root cause is insufficient authorization validation in the credentialed execution path. The ExecTool.Execute implementation trusts caller-supplied context without enforcing the privilege boundary appropriate for the requested tool. As a result, a low-privileged caller can reach execution logic reserved for higher-privileged operations.

Attack Vector

An attacker authenticates to a GoClaw instance and issues a crafted request that invokes ExecTool.Execute. The manipulated parameters cause the authorization logic to accept the request even though the principal lacks the required rights. See the GitHub PoC Repository and GitHub Issue #1215 for technical details.

No verified proof-of-concept code is reproduced here. Refer to the VulDB CVE-2026-16199 entry for exploit context.

Detection Methods for CVE-2026-16199

Indicators of Compromise

Unexpected invocations of ExecTool.Execute originating from low-privileged user sessions.
Log entries showing credentialed tool executions that do not correspond to legitimate administrative workflows.
Repeated requests from a single authenticated principal targeting the credentialed execution endpoint.

Detection Strategies

Enable verbose audit logging on GoClaw and alert on any credentialed_exec.go code path invocation.
Correlate authenticated session privileges against the actual tool being executed to identify authorization mismatches.
Baseline normal usage of ExecTool.Execute and flag deviations in caller identity, frequency, or arguments.

Monitoring Recommendations

Forward GoClaw application logs to a centralized SIEM for retention and analysis.
Monitor authentication events for accounts that suddenly begin invoking privileged tool execution endpoints.
Track network requests to GoClaw API endpoints and alert on anomalous request patterns.

How to Mitigate CVE-2026-16199

Immediate Actions Required

Restrict network access to GoClaw instances so only trusted users and hosts can reach the application.
Review all accounts with authenticated access and remove any that are not strictly required.
Audit recent GoClaw logs for suspicious invocations of ExecTool.Execute prior to remediation.

Patch Information

At the time of publication, no fixed release beyond 3.13.3-beta.3 has been referenced in NVD. Monitor the GoClaw GitHub repository and the associated GitHub Issue #1215 for a patched release and upgrade guidance.

Workarounds

Place GoClaw behind an authenticated reverse proxy that enforces additional authorization checks before requests reach ExecTool.Execute.
Disable or remove credentialed tool execution features if they are not required in your deployment.
Apply the principle of least privilege by scoping application credentials to the minimum permissions necessary.

bash

# Example: restrict access to GoClaw via host-based firewall rules
# Allow only trusted management subnet, deny all other inbound traffic
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP