CVE-2026-59726 is a critical-severity (CVSS 10) OS Command Injection vulnerability. A fix is available — see the affected versions and patch details below.
Ruflo: Unauthenticated RCE in MCP bridge default docker-compose deployment
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-59726.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-59726 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Ruflo is an agent meta-harness for Claude Code and Codex. Prior to 3.16.3, ruflo's default docker-compose deployment exposed the MCP bridge POST /mcp and POST /mcp/:group endpoints without authentication, allowing an unauthenticated network attacker to invoke tools/call to terminal_execute, obtain a shell in the bridge container, read provider API keys, and poison AgentDB learning-store patterns. This issue is fixed in version 3.16.3.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2026-59726, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
How to detect CVE-2026-59726
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2026-59726 -u https://target- Template
- ruflo MCP Bridge - Unauthenticated RCE via terminal_execute
- Severity
- critical
- Impact
- Unauthenticated remote code execution. An attacker can read provider API keys (OPENAI_API_KEY, ANTHROPIC_API_KEY, etc.) from the container environment, spawn attacker-controlled swarms on victim keys, and persist poisoned patterns into AgentDB.
- Remediation
- Upgrade ruflo to version 3.16.3 or later which adds DANGEROUS_TOOLS gate in executeTool(), bearer auth middleware (MCP_AUTH_TOKEN), loopback bind by default (BIND_HOST=127.0.0.1), and MCP_ENABLE_TERMINAL opt-in. As interim mitigation, firewall port 3001 and set MCP_AUTH_TOKEN in docker-compose.yml.
Template by ProjectDiscovery nuclei-templates (DhiyaneshDk), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2026-59726 in your dependencies?
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