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Critical CVSS 9.8

CVE-2026-5270

NVD analysis in progress

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.

What this means

Exposure
Exploitable remotely over the network, without authentication and with no action from the victim.
Impact
An attacker can read sensitive data, modify or destroy data and take the service offline.
Weakness
The authentication mechanism can be bypassed, letting an attacker pose as a legitimate user.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doPatch without waiting for the next scheduled cycle. Start with the instances exposed to the internet.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
14 July 2026
CVSS
9.8 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.45% probability of exploitation within 30 days · above 37% of all CVEs
Weakness
CWE-287
Sources
nvd
References

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