CVE-2026-9153: Rapid7 InsightConnect Sed Plugin Arbitrary File Read Vulnerability

Technical summary

CVE-2026-9153 is an arbitrary file read vulnerability affecting the Rapid7 InsightConnect Sed Plugin on Linux environments. The vulnerability stems from insufficient input validation on the expression parameter, allowing authenticated attackers to manipulate sed commands to access files beyond intended scope. The attack requires valid authentication credentials and network access to the InsightConnect instance, but does not require user interaction. The vulnerability maps to CWE-200 (Information Exposure) and CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), indicating both exposure of sensitive information and path traversal weaknesses in input handling.

Business impact

Organizations using Rapid7 InsightConnect with the Sed Plugin in Linux environments face confidentiality risk if the automation platform has access to sensitive configuration files, credentials, or business data. An authenticated insider or compromised account can exfiltrate files without leaving obvious traces in workflow logs. The impact is contained to information disclosure—the vulnerability does not enable file modification or system compromise—but unauthorized data access can violate compliance obligations and expose proprietary information depending on what files the service can reach.

Affected systems

The vulnerability specifically affects the Sed Plugin component within Rapid7 InsightConnect running on Linux systems. Rapid7 InsightConnect is commonly deployed as a security orchestration, automation, and response (SOAR) platform. Systems are vulnerable only if: (1) InsightConnect is installed and running, (2) the Sed Plugin is enabled or installed, (3) the environment is Linux-based, and (4) the instance permits authenticated access to plugin functions. Organizations should audit their InsightConnect deployments to identify which versions include the vulnerable Sed Plugin and whether the plugin is actively used in automation workflows.

Exploitability

Exploitability is moderate. The vulnerability requires valid authentication credentials to InsightConnect, which limits the attack surface to authorized users, privileged insiders, or attackers with stolen credentials. There is no user interaction required once authenticated. The attack is network-accessible and relatively straightforward to execute—an attacker needs only to invoke the Sed Plugin with a crafted expression parameter. However, the vulnerability is not currently tracked in the CISA Known Exploited Vulnerabilities (KEV) catalog, suggesting active exploitation in the wild has not been publicly confirmed, though this does not guarantee absence of private exploitation.

Remediation

Organizations should immediately verify their Rapid7 InsightConnect version and Sed Plugin status. Remediation requires applying a vendor patch; verify the specific patched version number against the Rapid7 security advisory. As an interim measure, restrict network and administrative access to InsightConnect instances to necessary users only, disable the Sed Plugin if not required for critical workflows, and monitor authentication logs for suspicious access patterns. Review recent automation logs to identify any unusual sed expression usage that may indicate exploitation attempts.

Patch guidance

Contact Rapid7 for the patched version of InsightConnect that resolves CVE-2026-9153. Verify the specific patch version number and compatibility notes in the official Rapid7 security advisory before deploying. Test patches in a non-production environment to ensure compatibility with existing automation workflows and integrations. Given the authentication requirement, patching can often be scheduled during normal maintenance windows, but prioritize based on the sensitivity of files accessible to the InsightConnect service account.

Detection guidance

Monitor InsightConnect logs and audit trails for unusual Sed Plugin invocations, particularly with expression parameters containing special characters or path traversal sequences (e.g., '../', '..\', absolute paths). Alert on expression parameters that reference system files or configuration directories outside normal workflow patterns. Correlate InsightConnect activity with file access logs on the underlying Linux system to identify unauthorized file reads by the service account. Network-based detection is limited; focus on application and host-level logging.

Why prioritize this

Although rated MEDIUM severity (CVSS 6.5), this vulnerability warrants prompt attention for organizations using InsightConnect because it affects information confidentiality in a platform that often has elevated privileges and access to sensitive infrastructure data. The authentication requirement reduces risk compared to unauthenticated exploits, but the lack of user interaction and network accessibility mean a compromised service account or malicious insider can quickly extract sensitive information. Prioritize based on the sensitivity of files the InsightConnect service account can access.

Risk score, explained

The CVSS 3.1 score of 6.5 reflects a MEDIUM severity rating driven by high confidentiality impact (reading arbitrary files) combined with the requirement for prior authentication, which lowers the attack vector severity. The network-accessible attack vector and lack of user interaction prevent a higher score, but the absence of complexity requirements and the broad scope of readable files keep the score in the mid-range. Organizations with highly sensitive data accessible to InsightConnect should treat this as a priority despite the MEDIUM label.

Frequently asked questions