CVE-2026-18038 Overview
CVE-2026-18038 is an information disclosure vulnerability affecting nextlevelbuilder GoClaw up to version 3.13.2. The flaw resides in the ExecTool.Execute function within goclaw/internal/http/tools_invoke.go, specifically in the jq Handler component. An authenticated remote attacker can manipulate input to the handler and obtain sensitive information from the application. The issue is tracked under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. A proof-of-concept exploit has been published publicly, and a fix is available in pull request #1230.
Critical Impact
Remote authenticated attackers can trigger the jq Handler in GoClaw ≤ 3.13.2 to disclose sensitive information processed by the ExecTool.Execute function.
Affected Products
- nextlevelbuilder GoClaw versions up to and including 3.13.2
- Deployments exposing the GoClaw HTTP jq Handler (goclaw/internal/http/tools_invoke.go)
- Any downstream application embedding vulnerable GoClaw builds
Discovery Timeline
- 2026-07-28 - CVE-2026-18038 published to NVD
- 2026-07-28 - Last updated in NVD database
Technical Details for CVE-2026-18038
Vulnerability Analysis
The vulnerability affects the ExecTool.Execute function inside goclaw/internal/http/tools_invoke.go, which implements the jq Handler used to process JSON queries in GoClaw. Attackers with low-privilege network access can craft manipulated requests that cause the handler to expose data it should not return to the caller. Because the attack is delivered over the network and requires no user interaction, exploitation can be automated against exposed GoClaw endpoints. The published proof-of-concept lowers the barrier for opportunistic abuse, even though the confidentiality impact is limited in scope.
Root Cause
The root cause is improper output handling within the jq Handler in ExecTool.Execute. The function returns data derived from jq processing without sufficient filtering, permitting sensitive fields to leak through the HTTP response path. This class of weakness is categorized as CWE-200. The upstream patch, Pull Request #1230, corrects the exposure introduced by the handler.
Attack Vector
Exploitation occurs remotely over HTTP against a GoClaw instance that exposes the tool invocation endpoint backed by the jq Handler. An attacker with authenticated low-privilege access sends a manipulated payload to the handler and inspects the response for disclosed information. No user interaction is required. Additional context is documented in GitHub Issue #1226 and VulDB entry #383813.
No verified exploit code is reproduced here. Refer to the GoClaw repository and associated tracker items for technical details.
Detection Methods for CVE-2026-18038
Indicators of Compromise
- Anomalous HTTP requests targeting GoClaw tool invocation endpoints that call the jq Handler
- Response payloads from ExecTool.Execute containing fields larger or more sensitive than expected for the requesting principal
- Repeated low-privileged sessions issuing jq queries with atypical filters or wildcards
Detection Strategies
- Inspect application logs from GoClaw for invocations of ExecTool.Execute correlated with unusual response sizes or content types
- Deploy web application firewall rules to flag jq Handler requests containing filter expressions that reference internal keys or metadata
- Compare current GoClaw binary or module version against 3.13.2 and confirm whether patch #1230 is applied
Monitoring Recommendations
- Enable verbose HTTP access logging on GoClaw instances, capturing request path, authenticated principal, and response length
- Alert on repeated requests to the tool invocation endpoint from a single low-privilege account within short time windows
- Track outbound data volume from GoClaw services to identify sustained information extraction patterns
How to Mitigate CVE-2026-18038
Immediate Actions Required
- Inventory all GoClaw deployments and identify instances running versions ≤ 3.13.2
- Apply the upstream fix from Pull Request #1230 or upgrade to a release that includes it
- Restrict network exposure of the GoClaw jq Handler endpoint to trusted callers only
- Rotate any credentials or tokens that may have transited the jq Handler while the vulnerable version was reachable
Patch Information
The maintainers merged the fix in GoClaw Pull Request #1230, referenced by the vendor as patch 1230. The related tracking issue is GitHub Issue #1226. Additional cross-references are available in VulDB CVE-2026-18038.
Workarounds
- Disable or gate the jq Handler route in goclaw/internal/http/tools_invoke.go until the patch is deployed
- Enforce stricter authorization checks in front of the tool invocation endpoint via reverse proxy or API gateway
- Limit jq Handler access to administrative accounts only, removing low-privilege access paths
- Apply egress filtering to reduce the impact of any partial information disclosure through the handler
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
