CVE-2026-56793: Dell OpenManage Authentication Bypass Flaw

CVE-2026-56793 Overview

CVE-2026-56793 is an improper authentication vulnerability [CWE-287] in Dell OpenManage Server Administrator (OMSA) versions prior to 11.1.0.2. The flaw allows an unauthenticated attacker with network access to bypass authentication controls and gain unauthorized access to the management interface. Dell published the advisory DSA-2026-326 to address the issue.

OMSA is deployed on Dell PowerEdge servers to provide remote hardware management, making exposed instances high-value targets. Successful exploitation impacts confidentiality, integrity, and availability of the affected host.

Critical Impact
An unauthenticated remote attacker can bypass authentication in Dell OpenManage Server Administrator and obtain unauthorized access to server management functionality.

Affected Products

Dell OpenManage Server Administrator versions prior to 11.1.0.2
Dell PowerEdge servers running vulnerable OMSA builds
Systems exposing the OMSA web management interface over the network

Discovery Timeline

2026-08-07 - CVE-2026-56793 published to NVD
2026-08-08 - Last updated in NVD database

Technical Details for CVE-2026-56793

Vulnerability Analysis

The vulnerability resides in the authentication logic of Dell OpenManage Server Administrator. OMSA exposes a web-based management interface and associated services that require authenticated sessions to perform privileged operations. Improper enforcement of authentication checks permits requests to reach protected functionality without a valid credentialed session.

The issue is remotely reachable over the network and requires no user interaction. Because OMSA operates with high privileges on the host to manage hardware, BIOS, RAID, and firmware, successful abuse yields broad control over the server. The Common Weakness Enumeration classification is [CWE-287] Improper Authentication.

At publication, no public proof-of-concept is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. EPSS data from 2026-08-14 places the exploitation probability at the lower end of the distribution, though this can change once technical details or exploit code are disclosed.

Root Cause

The root cause is a defect in how OMSA validates authentication state on inbound requests. Specific technical details, including the affected endpoint and authentication mechanism, are not enumerated in the public advisory. Dell's advisory DSA-2026-326 characterizes the flaw as an improper authentication issue permitting unauthorized access.

Attack Vector

Exploitation requires network reachability to the OMSA management service. An attacker sends crafted requests to the management interface that bypass authentication controls and interact with functionality that should require valid credentials. No privileges and no user interaction are required, which broadens the range of viable attackers to include anonymous internet or intranet hosts that can route to the OMSA listener.

See the Dell Security Update Advisory for vendor guidance. No verified exploit code is available at this time.

Detection Methods for CVE-2026-56793

Indicators of Compromise

Unexpected authenticated sessions or API calls to OMSA endpoints originating from unknown source addresses.
Configuration changes, user additions, or firmware/BIOS modifications on PowerEdge hosts without corresponding change-management records.
OMSA log entries showing successful access preceded by no authentication events.

Detection Strategies

Inventory all Dell PowerEdge hosts and confirm the installed OMSA version against 11.1.0.2 using package managers or the OMSA omreport utility.
Compare current OMSA listener exposure (default TCP 1311) against network segmentation policy to identify internet-facing or overly reachable instances.
Correlate web server and OMSA application logs to identify requests to privileged handlers that lack a preceding authentication event.

Monitoring Recommendations

Alert on inbound connections to OMSA management ports from outside the management VLAN.
Monitor OMSA audit logs for privileged operations such as user creation, alert configuration changes, and remote command execution.
Forward OMSA and host telemetry to a centralized log platform for retention and correlation with endpoint activity.

How to Mitigate CVE-2026-56793

Immediate Actions Required

Upgrade Dell OpenManage Server Administrator to version 11.1.0.2 or later on all affected PowerEdge hosts.
Restrict access to the OMSA management interface (default port 1311) to trusted administrative networks only.
Audit OMSA accounts, session tokens, and recent management actions for signs of unauthorized activity.

Patch Information

Dell has released a fixed version of OMSA that resolves the improper authentication defect. Administrators should apply the update referenced in the Dell Security Update Advisory DSA-2026-326. Update all instances, including remote branch servers and standby hardware, to 11.1.0.2 or later.

Workarounds

Block network access to OMSA ports (1311/tcp and any custom-configured ports) at host and perimeter firewalls until patching is complete.
Disable the OMSA web server component on hosts where remote management via OMSA is not required.
Place OMSA behind a VPN or bastion host so that only authenticated administrators on the management network can reach the service.

bash

# Example: restrict OMSA (port 1311) to the management subnet on Linux hosts
sudo iptables -A INPUT -p tcp --dport 1311 -s 10.10.20.0/24 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 1311 -j DROP

# Verify installed OMSA version
omreport about | grep -i version