CVE-2026-16200: rt-claw Auth Bypass Vulnerability

CVE-2026-16200 Overview

CVE-2026-16200 is an incorrect authorization vulnerability in zevorn rt-claw versions up to 0.2.0. The flaw resides in the claw_tool_invoke function within claw/services/swarm/swarm.c, part of the Remote Procedure Call (RPC) handler component. Attackers can exploit the weakness remotely without authentication or user interaction. The exploit has been publicly disclosed, increasing the risk of opportunistic abuse. The maintainer received an early issue report but has not yet responded with a fix. The vulnerability is tracked under CWE-285: Improper Authorization.

Critical Impact
Remote attackers can invoke privileged RPC tool functions in rt-claw without proper authorization checks, compromising confidentiality, integrity, and availability of the affected service.

Affected Products

zevorn rt-claw versions up to and including 0.2.0
claw/services/swarm/swarm.c — RPC Handler component
The claw_tool_invoke function

Discovery Timeline

2026-07-19 - CVE-2026-16200 published to NVD
2026-07-20 - Last updated in NVD database

Technical Details for CVE-2026-16200

Vulnerability Analysis

The vulnerability is an improper authorization flaw [CWE-285] in the rt-claw swarm service. The claw_tool_invoke function processes incoming RPC requests but fails to enforce authorization checks on the caller before executing the requested tool operation. Because the RPC handler is reachable over the network, any remote client can trigger tool invocations that should be restricted to authorized principals.

Exploitation requires no authentication, no user interaction, and low attack complexity. The impact spans confidentiality, integrity, and availability, though each is limited in scope to the affected service. Public disclosure of the exploit lowers the barrier for opportunistic scanning and abuse against exposed rt-claw deployments.

Root Cause

The root cause is missing or insufficient authorization logic inside claw_tool_invoke. The function accepts and dispatches RPC tool requests without verifying that the caller holds the privileges required for the requested operation. Authentication state and access control policy are not evaluated before the sensitive branch executes.

Attack Vector

The attack vector is network-based. An attacker sends a crafted RPC request to a reachable rt-claw instance targeting the swarm service. Because claw_tool_invoke does not enforce authorization, the crafted request causes the handler to execute tool operations the caller should not be able to reach. See the GitHub issue tracker and the VulDB vulnerability report for technical context. No verified proof-of-concept code has been published to a trusted repository at this time.

Detection Methods for CVE-2026-16200

Indicators of Compromise

Unexpected RPC calls to the rt-claw swarm service from unknown or unauthenticated network sources.
Log entries showing successful claw_tool_invoke executions without a preceding authenticated session.
Tool invocations originating from IP addresses outside expected administrative ranges.

Detection Strategies

Enable verbose logging on the rt-claw RPC handler to capture caller identity, source address, and invoked tool name for every request.
Correlate RPC invocation events against authentication events to flag tool executions with no matching auth context.
Deploy network detection rules that alert on RPC traffic to rt-claw endpoints from untrusted network segments.

Monitoring Recommendations

Monitor outbound behavior of hosts running rt-claw for anomalous process activity after RPC calls.
Track version inventory to identify systems still running rt-claw 0.2.0 or earlier.
Watch the upstream repository and GitHub issue 133 for a maintainer response or patch commit.

How to Mitigate CVE-2026-16200

Immediate Actions Required

Restrict network access to the rt-claw RPC service using firewall rules or host-based ACLs, limiting exposure to trusted management networks.
Take affected rt-claw 0.2.0 instances offline if they are exposed to untrusted networks and no compensating controls exist.
Audit recent RPC handler logs for signs of unauthorized claw_tool_invoke calls.

Patch Information

No official patch is available at the time of publication. The maintainer received an early issue report through GitHub issue 133 but has not responded. Track the rt-claw repository for a fixed release above version 0.2.0 and the VulDB CVE entry for updates.

Workarounds

Place rt-claw behind an authenticating reverse proxy or service mesh that enforces mutual TLS and caller identity before requests reach the RPC handler.
Apply network segmentation so only vetted internal clients can reach the swarm service port.
Disable or remove the swarm service if it is not required for the deployment.
Add application-layer authorization checks in front of claw_tool_invoke if maintaining a local fork.

bash

# Example: restrict rt-claw RPC access with iptables to a trusted management subnet
iptables -A INPUT -p tcp --dport <rt-claw-rpc-port> -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport <rt-claw-rpc-port> -j DROP