CVE-2026-5270 — Authentication Bypass in Navigator and Blue Planet Products
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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.7% (30-day exploitation probability)+8
- Technical severity (critical)+10
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Blue Planet Inventory, Blue Planet Orchestration, Blue Planet Route Optimization & Analysis…).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Blue Planet | Inventory | version <=24.04.001version <=23.12.401version <=23.08.302version <=23.04.701 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Blue Planet | Orchestration | version <=24.04.2version <=23.12.3version <=23.08.4version <=23.04.2 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Blue Planet | Route Optimization & Analysis | version <=24.04.1.2-Rversion <=23.12.1.6-Rversion <=23.08.1.6-Rversion <=23.04.P01-9-R | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Blue Planet | Unified Assurance & Analytics | version <=23.04. MR4version <=23.12 MR3version <=24.04 MR1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| CIENA | MCP | version <= 8.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| CIENA | Navigator NCS | version 8.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| CIENA | Planner Plus OnPrem | version <= 4.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.8 | CVSS 3.1 | Critical | 3.9 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 9.8 | CVSS 3.1 | Critical | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · ciena/navigator ncs, ciena/mcp, ciena/planner plus onprem, blue planet/inventory, blue planet/orchestration, blue planet
- SSVC assessment updated
- Record published
- CVSS changed · 9.8
- Source status changed · → Awaiting Analysis
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-5267 Unauthenticated Event Stream Exposure of Session Tokens in Navigator NCS 20d
- Critical CVE-2026-5269 Navigator NCS and MCP System Accounts with Default Passwords Jul 14, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-5270 is "Authentication Bypass in Navigator and Blue Planet Products", rated Critical. It affects Inventory (Blue Planet); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 0.66% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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