CVE-2026-43575: OpenClaw Authentication Bypass Vulnerability

CVE-2026-43575 Overview

CVE-2026-43575 is an authentication bypass vulnerability affecting OpenClaw versions 2026.2.21 through versions before 2026.4.10. The flaw resides in the sandbox noVNC helper route, which fails to enforce bridge authentication before granting access. Unauthenticated attackers reaching the route over the network can interact with active browser sessions and harvest session credentials. The weakness is classified under CWE-862: Missing Authorization. Exploitation requires no privileges, no user interaction, and is reachable from the network.

Critical Impact
Remote unauthenticated attackers can hijack interactive browser sessions and steal credentials by accessing the noVNC helper route directly.

Affected Products

OpenClaw 2026.2.21 through versions before 2026.4.10
OpenClaw sandbox noVNC helper route component
OpenClaw bridge authentication subsystem

Discovery Timeline

2026-05-06 - CVE-2026-43575 published to NVD
2026-05-06 - Last updated in NVD database

Technical Details for CVE-2026-43575

Vulnerability Analysis

OpenClaw exposes a sandbox noVNC helper route used to render interactive browser sessions through a noVNC web client. In affected versions, this route does not consult the bridge authentication layer before serving session content. As a result, any network-reachable client can request the helper endpoint and connect to a live browser session without presenting valid credentials.

Once connected, the attacker observes and controls the same browser context held by an authenticated user. This includes cookies, authentication tokens, form data, and any in-progress workflow inside the sandboxed browser. The authentication boundary that should isolate the helper from untrusted callers is absent, collapsing confidentiality, integrity, and availability of the sandboxed session into a single failed check.

Root Cause

The root cause is a missing authorization check on the noVNC helper route. The bridge authentication mechanism that gates other sandbox functionality is not applied to this specific endpoint. The 8dfbf3268bd224b7377d1ecca77a445100746085 commit adds the required authentication enforcement, aligning the helper route with the rest of the bridge surface. See the GitHub Security Advisory GHSA-92jp-89mq-4374 for vendor details.

Attack Vector

An attacker identifies an OpenClaw deployment exposing the sandbox noVNC helper route on the network. The attacker issues a direct HTTP request to the helper endpoint without supplying bridge authentication. The server returns interactive session access, granting credential exposure and full control over the browser session. No prior account, token, or social engineering step is required. Refer to the VulnCheck Authentication Bypass Advisory for additional context.

No verified public exploit code is available at this time. The vulnerability mechanism is documented in the upstream advisory and patch.

Detection Methods for CVE-2026-43575

Indicators of Compromise

HTTP requests to OpenClaw noVNC helper routes that do not include bridge authentication headers or tokens
WebSocket upgrade requests to the noVNC endpoint originating from unexpected source addresses or user agents
Concurrent noVNC sessions tied to a single sandbox instance, indicating an unauthorized observer
Outbound credential reuse from systems whose sessions were rendered through OpenClaw sandboxes

Detection Strategies

Inspect reverse proxy and application logs for 200 responses on the noVNC helper path without preceding bridge authentication events
Alert on direct access to noVNC routes from networks outside the expected administrative range
Correlate sandbox session start events with bridge authentication events; flag sessions that lack a paired authentication record

Monitoring Recommendations

Forward OpenClaw application, proxy, and WebSocket logs to a centralized analytics platform for retention and correlation
Track baseline volumes of noVNC helper requests and alert on deviations
Monitor for unexpected egress from sandboxed browser sessions, which may indicate session hijack and credential exfiltration

How to Mitigate CVE-2026-43575

Immediate Actions Required

Upgrade OpenClaw to version 2026.4.10 or later, which enforces bridge authentication on the noVNC helper route
Restrict network access to OpenClaw sandbox endpoints so only trusted management networks can reach the noVNC helper
Rotate any credentials, cookies, or tokens that were exposed within sandboxed browser sessions during the affected window

Patch Information

The fix is delivered in OpenClaw version 2026.4.10 and is implemented in commit 8dfbf3268bd224b7377d1ecca77a445100746085. The patch adds authorization enforcement to the noVNC helper route so that requests without valid bridge authentication are rejected. Vendor guidance is published in GitHub Security Advisory GHSA-92jp-89mq-4374.

Workarounds

Block external access to the noVNC helper route at the reverse proxy or firewall until the upgrade is applied
Require mutual TLS or an authenticated proxy in front of OpenClaw to deny unauthenticated callers
Disable the sandbox noVNC helper feature in environments where interactive browser sessions are not required

bash

# Configuration example: restrict noVNC helper route at reverse proxy (nginx)
location /sandbox/novnc/ {
    allow 10.0.0.0/8;        # trusted management network
    deny all;
    auth_request /_bridge_auth;
    proxy_pass http://openclaw_backend;
}