CVE-2026-9153 Overview
CVE-2026-9153 is an arbitrary file read vulnerability in the Rapid7 InsightConnect Sed Plugin on Linux. Authenticated attackers can read arbitrary files on the host by supplying crafted input to the expression parameter. The flaw stems from insufficient input validation, which allows path traversal sequences to escape the intended file context. The issue is tracked under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory).
Critical Impact
Authenticated attackers can exfiltrate sensitive files, including credentials, configuration data, and orchestration secrets accessible to the plugin runtime user.
Affected Products
- Rapid7 InsightConnect Sed Plugin (Linux)
- Refer to the Rapid7 Extension Overview for plugin version details
- Deployments using the Sed plugin within InsightConnect orchestration workflows
Discovery Timeline
- 2026-06-25 - CVE-2026-9153 published to the National Vulnerability Database
- 2026-06-25 - Last updated in NVD database
Technical Details for CVE-2026-9153
Vulnerability Analysis
The Sed plugin exposes an expression parameter intended to carry sed-style text transformation expressions. The plugin fails to sanitize or constrain input passed through this parameter before it reaches file handling logic. As a result, an authenticated user invoking the plugin action can supply a value that causes the underlying sed process to read files outside the intended scope.
Because sed natively supports reading from arbitrary file paths through expression directives such as r filename, untrusted expression input gives the attacker direct control over which files the plugin reads. The plugin returns the file contents in its action output, completing the disclosure path. The attack requires only standard authenticated access to the InsightConnect environment and no user interaction. Confidentiality impact is high, while integrity and availability are not affected.
Root Cause
The root cause is missing validation on the expression parameter before it is concatenated into the sed invocation. The plugin trusts caller-supplied expressions and does not strip or reject file-reference directives, traversal sequences such as ../, or absolute paths pointing to sensitive locations including /etc/passwd, /etc/shadow, or InsightConnect configuration files.
Attack Vector
An authenticated attacker triggers the vulnerable Sed plugin action through a workflow or direct API call. The attacker supplies an expression value that instructs sed to read a target file path. The plugin executes the expression and returns the contents of the targeted file in the action result, which the attacker retrieves through the orchestration job output.
No verified public exploit code is available. Defenders should consult the Rapid7 Extension Overview for plugin-specific guidance.
Detection Methods for CVE-2026-9153
Indicators of Compromise
- Sed plugin executions where the expression parameter contains file paths, traversal sequences (../), or sed read directives such as r /path/to/file
- Plugin job logs returning unexpected file contents, particularly system files like /etc/passwd, /etc/shadow, or .env files
- Unusual workflow invocations of the Sed plugin from accounts that do not normally author text-transformation jobs
Detection Strategies
- Review InsightConnect audit logs for Sed plugin actions and inspect the expression parameter values for suspicious patterns
- Correlate plugin execution events with the identity of the invoking user to identify low-privilege accounts performing reconnaissance
- Alert on plugin output payloads that contain content signatures matching sensitive files such as Linux user databases or private keys
Monitoring Recommendations
- Forward InsightConnect orchestrator and plugin runtime logs to a centralized SIEM with retention sufficient for incident reconstruction
- Monitor the plugin host for file access events involving sensitive directories executed by the InsightConnect service account
- Track baseline usage of the Sed plugin and flag deviations in frequency, source user, or expression length
How to Mitigate CVE-2026-9153
Immediate Actions Required
- Upgrade the InsightConnect Sed Plugin to the latest version published on the Rapid7 Extension Overview page
- Restrict which InsightConnect users and workflows can invoke the Sed plugin action
- Audit recent Sed plugin executions for malicious expression values and rotate any credentials that may have been exposed
Patch Information
Refer to Rapid7's plugin distribution channel for the patched Sed plugin release. Consult the Rapid7 Extension Overview for the current supported version and update procedure within the InsightConnect orchestrator.
Workarounds
- Disable the Sed plugin in workflows where it is not strictly required
- Apply least-privilege controls so the InsightConnect service account cannot read sensitive system files
- Implement workflow-level input validation that rejects expression values containing file paths or sed read directives
# Example: restrict InsightConnect service account file access on Linux
# Run the orchestrator under a dedicated user with minimal filesystem rights
sudo chown -R insightconnect:insightconnect /opt/rapid7/insightconnect
sudo chmod 750 /opt/rapid7/insightconnect
# Remove read access to sensitive files for the service account group
sudo setfacl -m g:insightconnect:--- /etc/shadow
sudo setfacl -m g:insightconnect:--- /root
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
