Vulnerability · Published Jul 14, 2026 · Assigned by Ciena
CVE-2026-5269Navigator NCS and MCP System Accounts with Default Passwords
Critical 9.8
In plain English
A critical-severity security flaw in MCP from CIENA. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).
Official description
In Ciena's Navigator Network Control Suite (NCS) and Manage Control Plan (MCP), there are hidden system accounts used for internal software operations. Some of these accounts have default passwords that may be predictable. While these accounts have very limited permissions on their own, an attacker could combine an attack using one of these accounts with other potential weaknesses to launch a more significant attack, possibly leading to escalation of privilege on the system.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| CIENA | Navigator NCS | 8.1 |
| CIENA | MCP | <= 8.0 |
| CIENA | Planner Plus OnPrem | <= 4.1 |
Weakness: CWE-1393 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H