Critical HPE Fabric Composer Flaws Allow Remote Code Execution

Key Takeaways

• HPE has addressed a series of critical vulnerabilities in its Networking Fabric Composer product.
• These flaws, some with a maximum CVSS score of 10.0, could allow unauthenticated remote attackers to gain full administrative control.
• Versions 7.3.3 and earlier of HPE Networking Fabric Composer are affected.
• Patches are available in versions 7.4.0 (or later in the 7.4 branch) and 7.3.4 (or later in the 7.3 branch).

Critical Flaws Expose HPE Fabric Composer to Remote Exploits

Hewlett Packard Enterprise (HPE) has released urgent security updates for its Networking Fabric Composer software to mitigate a comprehensive set of vulnerabilities. These newly discovered flaws could enable unauthenticated attackers to achieve complete system compromise, including gaining administrator privileges and executing arbitrary commands remotely.

The affected product, HPE Networking Fabric Composer, in versions 7.3.3 and earlier, is a crucial platform for managing and automating data-center network fabrics. A successful exploit of these vulnerabilities therefore poses a significant risk, as it could grant an attacker control over essential network infrastructure.

High-Severity Vulnerabilities Detailed

Among the most critical issues identified are CVE-2026-76657 and CVE-2026-76658, both of which have been assigned the maximum CVSS score of 10.0, indicating extreme severity.

CVE-2026-76657 describes an API authentication-bypass vulnerability. HPE states that a remote attacker could exploit this flaw to bypass existing authentication mechanisms, thereby obtaining administrative access without needing valid credentials. This unauthorized access could lead to a complete takeover of the Fabric Composer host.

The second critical vulnerability, CVE-2026-76658, impacts the product’s SSH daemon. This flaw permits an unauthenticated remote attacker to gain administrative access and execute arbitrary commands with privileged user permissions on the underlying operating system.

Exploiting these vulnerabilities could allow an attacker to seize control of the appliance, modify its configurations, exfiltrate sensitive data, or establish a foothold for deeper penetration into an organization’s network.

HPE also addressed CVE-2026-19766, an authentication bypass affecting adjacent network segments, rated 9.6 on the CVSS scale. This vulnerability could allow an unauthenticated attacker on a connected network to execute arbitrary code with privileged operating-system permissions.

The list of patched vulnerabilities is extensive and includes other serious issues such as unauthenticated remote code execution flaws, stored cross-site scripting vulnerabilities, command injection, arbitrary file write capabilities, SQL injection, privilege escalation, information disclosure, and denial-of-service bugs.

Several of these weaknesses are particularly concerning due to their potential for chaining. An attacker might, for instance, leverage an information-disclosure bug to map internal services before exploiting an authentication bypass or remote code execution flaw to seize control of the server. Furthermore, lower-privileged Fabric Composer users could potentially escalate to administrative access by exploiting certain API and web interface flaws.

HPE’s internal security researchers were credited with discovering these vulnerabilities. At the time of the advisory’s publication, HPE confirmed it had no knowledge of public exploit code or active discussions targeting these issues.

Despite the absence of active exploits, the broad scope and high severity of these vulnerabilities underscore the critical importance of immediate patching, particularly for systems where management interfaces are exposed to untrusted networks.

What You Should Do

• Immediately upgrade HPE Networking Fabric Composer to version 7.4.0 or any later release within the 7.4 branch.
• Alternatively, if using the 7.3 branch, upgrade to version 7.3.4 or a later release.
• For older releases that have reached End of Maintenance, assume they are potentially exposed unless HPE has provided explicit guidance otherwise.
• As a best practice, HPE also recommends restricting command-line and web-based management interfaces to a dedicated Layer 2 segment or VLAN.
• Implement and enforce Layer 3 firewall controls to limit access to Fabric Composer management interfaces.
• Utilize logging and accounting controls to diligently track access and user activity on Fabric Composer systems for any suspicious behavior.
• Review all administrator accounts, SSH exposure, API access configurations, and network management logs for any indicators of compromise.

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