Navigator NCS: Improper Authentication
CVE-2026-5270 is a critical-severity improper authentication vulnerability in Navigator NCS from CIENA, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Navigator NCS versions: 8.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Navigator NCS you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| CIENA | Navigator NCS | 8.1 | Not stated |
| CIENA | MCP | <= 8.0 | Not stated |
| CIENA | Planner Plus OnPrem | <= 4.1 | Not stated |
| Blue Planet | Inventory | <=24.04.001; <=23.12.401; <=23.08.302; <=23.04.701 | Not stated |
| Blue Planet | Orchestration | <=24.04.2; <=23.12.3; <=23.08.4; <=23.04.2 | Not stated |
| Blue Planet | Route Optimization & Analysis | <=24.04.1.2-R; <=23.12.1.6-R; <=23.08.1.6-R; <=23.04.P01-9-R | Not stated |
| Blue Planet | Unified Assurance & Analytics | <=24.04 MR1; <=23.12 MR3; <=23.04. MR4 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
An authentication bypass vulnerability exists in certain releases of Ciena Navigator Network Control Suite (NCS), Manage Control Plan (MCP), and Blue Planet products. The issue is caused by improper handling of HTTP request paths and headers, which allows an unauthenticated attacker to manipulate requests in a manner that bypasses authentication and associated audit logging controls.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Navigator NCS
- 7.5 High severity
- 9.8 Critical severity
Recent Improper Authentication vulnerabilities
- 9.1 Critical severity
- 8.7 High severity
- 7.3 High severity
- 7.3 High severity
- 7.3 High severity
- 10.0 Critical severity
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