CVE-2026-5268Network attack vector

Unauthenticated filesystem read and write access

Published Jul 6, 2026 · Updated Jul 6, 2026

Authentication bypass in affected Ciena 6500 and CPL releases allows remote attackers to read or modify files through the default SFTP server. Ciena identifies the default SFTP server as the affected component but has not disclosed the alternate path, channel, or validation error that accepts an unauthenticated session. Network access to the SFTP service is the only published gate; no credentials or user interaction are required, and impact is limited to filesystem reads and writes.

CVSS severity9.1
Critical
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in affected Ciena 6500 and CPL releases allows remote attackers to read or modify files through the default SFTP server. Ciena identifies the default SFTP server as the affected component but has not disclosed the alternate path, channel, or validation error that accepts an unauthenticated session. Network access to the SFTP service is the only published gate; no credentials or user interaction are required, and impact is limited to filesystem reads and writes.

The record

CVE
CVE-2026-5268
Published
Jul 6, 2026
Updated
Jul 6, 2026
Vendor
Ciena
Product
6500 S-Series
Classifications
CWE-288, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=R16.96 and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ciena · 6500 S-Seriesversion=R16.96 and prior
Ciena · 6500 Packet Transport Systemversion=R16.1 and prior
Ciena · Common Photonic Layerversion=R12.63 and prior
Ciena · 6500 T-Seriesversion=R16.1 and prior

Published CVSS scores

9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-288Authentication Bypass Using an Alternate Path or Channel
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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