CVE-2026-26355 Overview
CVE-2026-26355 is an OS command injection vulnerability [CWE-78] affecting Dell PowerProtect Data Domain running the Data Domain Operating System (DDOS). The flaw stems from improper neutralization of special elements passed to an operating system command. A remote attacker with high privileges can inject arbitrary commands that execute in the underlying OS context. Dell disclosed the issue in advisory DSA-2026-278, which addresses multiple vulnerabilities in PowerProtect Data Domain.
Critical Impact
Authenticated remote attackers can execute arbitrary operating system commands on backup appliances, threatening the integrity and availability of enterprise backup infrastructure.
Affected Products
- Dell PowerProtect Data Domain versions 7.7.1.0 through 8.7
- Dell PowerProtect Data Domain LTS2026 versions 8.6.1.0 through 8.6.1.10, and LTS2025 versions 8.3.1.0 through 8.3.1.30
- Dell PowerProtect Data Domain LTS2024 versions 7.13.1.0 through 7.13.1.70
Discovery Timeline
- 2026-07-03 - CVE-2026-26355 published to the National Vulnerability Database
- 2026-07-08 - Last updated in NVD database
Technical Details for CVE-2026-26355
Vulnerability Analysis
CVE-2026-26355 is classified as an OS command injection weakness [CWE-78] in the Dell Data Domain Operating System. The affected component fails to sanitize user-supplied input before passing it to a shell or command interpreter. An attacker who supplies specially crafted arguments containing shell metacharacters can break out of the intended command context. The injected commands run with the privileges of the DDOS service handling the request.
Dell PowerProtect Data Domain appliances centralize deduplicated backup data for enterprise environments. Command execution on these systems can expose backup catalogs, retention policies, and replication configuration. The EPSS score is 1.052% (percentile 60.301) as of 2026-07-09.
Root Cause
The root cause is missing input neutralization on parameters that are later concatenated into an operating system command string. When input is passed directly to a shell without argument arrays or strict allow-list validation, characters such as ;, &, |, backticks, and $() alter the command's structure. The DDOS management interface accepts these inputs from an authenticated context but does not enforce a safe execution path.
Attack Vector
Exploitation requires network access to the Data Domain management interface and authentication as a high-privilege user. No user interaction is required. Once authenticated, the attacker submits a request containing shell metacharacters embedded in an otherwise valid parameter. The appliance interprets the payload and executes the attacker-controlled commands, resulting in high impact to integrity and availability while confidentiality is not directly affected.
No public proof-of-concept exploit code is available for CVE-2026-26355. See the Dell Security Update DSA-2026-278 for vendor-supplied technical details.
Detection Methods for CVE-2026-26355
Indicators of Compromise
- Unexpected child processes spawned by DDOS management or CLI daemons, particularly shells such as sh, bash, or utilities like curl, wget, and nc.
- Audit log entries showing administrative CLI commands that contain shell metacharacters (;, |, &&, backticks, $()) in argument fields.
- Outbound network connections from the Data Domain appliance to non-standard destinations following administrative sessions.
Detection Strategies
- Correlate authentication events for high-privilege accounts with subsequent process-creation events on the appliance management plane.
- Baseline expected administrative commands and alert on argument patterns containing shell control characters.
- Monitor for anomalous file writes to temporary directories or modifications to system binaries following privileged sessions.
Monitoring Recommendations
- Forward DDOS audit logs and syslog output to a centralized SIEM for correlation with identity and network telemetry.
- Enable alerting on privileged account logins from unexpected source IP ranges or outside change windows.
- Track configuration changes, replication target modifications, and retention lock policy edits in near real time.
How to Mitigate CVE-2026-26355
Immediate Actions Required
- Apply the fixed release identified in Dell advisory DSA-2026-278 for your applicable LTS branch or mainline version.
- Restrict network access to the Data Domain management interface to a dedicated administrative network or jump host.
- Rotate credentials for high-privilege DDOS accounts and audit which identities hold administrative roles.
- Review recent audit logs for suspicious command arguments or unexpected privileged sessions.
Patch Information
Dell has published fixes in advisory DSA-2026-278. Administrators should upgrade to a version beyond the affected ranges: 8.7 on the mainline branch, 8.6.1.10 on LTS2026, 8.3.1.30 on LTS2025, and 7.13.1.70 on LTS2024. Refer to the Dell Security Update DSA-2026-278 for the exact fixed builds and upgrade guidance.
Workarounds
- Limit administrative access using network segmentation, firewall ACLs, and VPN gating until patches are applied.
- Enforce multi-factor authentication and least privilege for all Data Domain administrative accounts to reduce the pool of users who could satisfy the high-privilege prerequisite.
- Enable and centrally collect DDOS audit logging so any exploitation attempt produces reviewable evidence.
# Example: restrict management interface exposure at the network edge
iptables -A INPUT -p tcp --dport 443 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
