CVE-2026-66269 Overview
Dell OpenManage Server Administrator (OMSA) contains an unsafe reflection vulnerability in versions prior to 11.1.0.3. The flaw stems from the use of externally-controlled input to select classes or code [CWE-470]. An unauthenticated remote attacker can exploit this weakness over the network to bypass protection mechanisms in the affected product. Dell has released a security update through advisory DSA-2026-403 addressing the issue.
Critical Impact
An unauthenticated remote attacker can bypass protection mechanisms in Dell OMSA by supplying attacker-controlled input that influences class or code selection during runtime reflection.
Affected Products
- Dell OpenManage Server Administrator (OMSA) versions prior to 11.1.0.3
Discovery Timeline
- 2026-09-17 - CVE CVE-2026-66269 published to NVD
- 2026-09-17 - Last updated in NVD database
Technical Details for CVE-2026-66269
Vulnerability Analysis
Dell OMSA is a systems management agent that exposes a web-based and programmatic interface for monitoring and configuring Dell server hardware. The vulnerability is classified as Unsafe Reflection [CWE-470], meaning application code uses externally supplied data to determine which class, method, or code path to instantiate at runtime.
Because the affected endpoint is reachable over the network without authentication, an attacker can influence reflective class loading to reach code paths that were not intended to be exposed. The documented impact is a bypass of protection mechanisms rather than direct code execution, but such bypasses commonly serve as primitives for further attack chains.
Root Cause
The root cause is the use of externally-controlled input as a selector for classes or code loaded through reflection. When user-supplied strings map directly to class names or method identifiers without a strict allowlist, an attacker can steer execution toward classes that grant unintended capabilities or that circumvent security checks enforced by the intended handlers.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker who can reach the OMSA management interface, typically exposed on management VLANs or, in misconfigured environments, on general networks, can send crafted requests that manipulate the reflection selector. See the Dell Security Update for OMSA (DSA-2026-403) for vendor-provided technical details.
No public proof-of-concept code is available at the time of publication.
Detection Methods for CVE-2026-66269
Indicators of Compromise
- Unexpected HTTP or HTTPS requests to OMSA management endpoints from untrusted network segments.
- Requests containing fully qualified Java class names or unusual serialized parameter values targeting OMSA handlers.
- OMSA process spawning child processes or loading classes outside its normal runtime profile.
Detection Strategies
- Inspect web server and application logs on hosts running OMSA for anomalous parameter values that resemble class names or package paths.
- Correlate authentication events with administrative actions to identify unauthenticated requests reaching privileged handlers.
- Baseline the OMSA service behavior and alert on deviations in loaded modules, spawned processes, or outbound network connections.
Monitoring Recommendations
- Enable verbose logging on the OMSA web interface and forward logs to a central analytics platform for retention and search.
- Monitor management network segments for scanning activity targeting default OMSA ports such as 1311/tcp.
- Track versions of OMSA across the fleet and alert when hosts remain on versions prior to 11.1.0.3.
How to Mitigate CVE-2026-66269
Immediate Actions Required
- Upgrade Dell OpenManage Server Administrator to version 11.1.0.3 or later on all managed servers.
- Restrict network access to the OMSA management interface to trusted administrative networks only.
- Audit exposure of OMSA endpoints from untrusted networks and remove any unintended internet exposure.
Patch Information
Dell has released a fixed version of OMSA. Administrators should apply the update referenced in the Dell Security Update for OMSA (DSA-2026-403). Upgrade to OMSA 11.1.0.3 or later to remediate the unsafe reflection weakness.
Workarounds
- Place OMSA hosts behind firewall rules that allow only management workstations to reach the service.
- Disable the OMSA web interface on servers where it is not actively required for operations.
- Where feasible, terminate OMSA behind a reverse proxy that enforces authentication and strict input validation before requests reach the service.
# Example firewall rule restricting OMSA (1311/tcp) to a management subnet
iptables -A INPUT -p tcp --dport 1311 -s 10.10.50.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 1311 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
