CVE-2026-15627: GoClaw Information Disclosure Vulnerability

CVE-2026-15627 Overview

CVE-2026-15627 is an information disclosure vulnerability affecting nextlevelbuilder GoClaw versions up to 3.13.3-beta.3. The flaw resides in the handleNavigate function within pkg/browser/tool.go. Manipulation of the args.targetUrl argument leads to unauthorized information disclosure [CWE-200]. The vulnerability is remotely exploitable and requires low-level privileges but no user interaction. A public exploit has been disclosed, increasing the likelihood of opportunistic exploitation attempts against unpatched instances.

Critical Impact
Remote attackers with low privileges can trigger information disclosure through crafted targetUrl arguments passed to the handleNavigate function, with a public exploit already available.

Affected Products

nextlevelbuilder GoClaw versions up to and including 3.13.3-beta.3
Component: pkg/browser/tool.go
Affected function: handleNavigate

Discovery Timeline

2026-07-14 - CVE-2026-15627 published to NVD
2026-07-14 - Last updated in NVD database

Technical Details for CVE-2026-15627

Vulnerability Analysis

The vulnerability is classified as an information exposure issue [CWE-200] within the GoClaw browser tooling component. GoClaw is a Go-based project maintained on GitHub by nextlevelbuilder. The affected code path lies in the handleNavigate function inside pkg/browser/tool.go, which processes navigation requests derived from caller-supplied arguments.

When an attacker manipulates the args.targetUrl parameter, the function fails to enforce adequate restrictions on the destination or context of the navigation. This allows sensitive information to be returned to or accessible by the attacker. According to the referenced VulDB entry, a working exploit is publicly available.

Root Cause

The root cause is insufficient validation and access control on the args.targetUrl input passed to handleNavigate. The function processes attacker-controlled URLs without adequately restricting the scope of navigation or filtering the data returned. This design gap enables disclosure of information that should not be exposed to a low-privileged remote requester.

Attack Vector

Exploitation occurs over the network and requires low-level privileges. An authenticated attacker sends a crafted request that invokes handleNavigate with a manipulated targetUrl value. Because the exploit is publicly available and no user interaction is required, opportunistic scanning and automated exploitation against exposed GoClaw instances are plausible.

No verified proof-of-concept code has been reproduced here. Refer to the GitHub Issue Tracker and VulDB Vulnerability Details for the disclosed technical write-up.

Detection Methods for CVE-2026-15627

Indicators of Compromise

Unexpected outbound navigation requests originating from the GoClaw browser tool component to attacker-controlled or unusual destinations.
Log entries showing calls to handleNavigate with targetUrl values pointing to internal resources, metadata endpoints, or non-standard schemes.
Anomalous response sizes or content returned from GoClaw navigation operations to authenticated but low-privileged users.

Detection Strategies

Enable verbose application logging on the GoClaw pkg/browser/tool.go code paths to capture the full targetUrl argument and requesting principal.
Correlate authentication logs with navigation events to identify low-privileged accounts issuing repeated or malformed navigation requests.
Deploy egress monitoring to flag GoClaw-initiated traffic to internal-only address ranges, cloud metadata services, or loopback interfaces.

Monitoring Recommendations

Baseline normal handleNavigate usage patterns and alert on deviations in request volume, URL structure, or destination class.
Ingest GoClaw application logs into a centralized SIEM or data lake for retention, correlation, and search across historical navigation activity.
Monitor the upstream GitHub Project Repository for new releases, patches, and advisories related to this issue.

How to Mitigate CVE-2026-15627

Immediate Actions Required

Inventory all deployments of nextlevelbuilder GoClaw and identify any instance running version 3.13.3-beta.3 or earlier.
Restrict network exposure of GoClaw endpoints to trusted networks and enforce least-privilege authentication for accounts able to invoke navigation functionality.
Review recent access logs for suspicious handleNavigate calls and investigate any anomalies against the indicators listed above.

Patch Information

No vendor-issued fixed version is referenced in the current NVD data. Track the GitHub Issue Tracker and the GitHub Project Repository for a patched release. Additional metadata is available in the VulDB CVE Reference.

Workarounds

Block or filter untrusted targetUrl values at an upstream proxy or application gateway before requests reach handleNavigate.
Implement an allowlist of permitted navigation destinations and reject any URL that does not match the approved scheme, host, and path pattern.
Revoke or downscope low-privileged accounts that do not require access to the browser tool component until a vendor fix is available.

bash

# Example egress allowlist enforcement at a reverse proxy
# Reject GoClaw navigation requests targeting internal or metadata endpoints
location /goclaw/navigate {
    if ($arg_targetUrl ~* "(169\.254\.169\.254|127\.0\.0\.1|localhost|10\.|192\.168\.)") {
        return 403;
    }
    proxy_pass http://goclaw_backend;
}