CVE-2026-5268
Critical
Description
An authentication bypass vulnerability exists in the default SFTP server component utilized across the Ciena products listed. This vulnerability allows a remote, unauthenticated attacker to bypass security controls and gain unauthorized access to the underlying filesystem. Successful exploitation could allow an attacker to read or modify system files.
SeverityCritical
CVSS9.1
Exploit probability—
Product6500 S-Series
PublishedJul 6, 2026
First seenJul 6, 2026
Weakness typeCWE-288CWE-288
How to fix
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| CIENA 6500 S-Series | R16.96 and prior | — |
| CIENA 6500 T-Series | R16.1 and prior | — |
| CIENA PTS | R16.1 and prior | — |
| CIENA CPL | R12.63 and prior | — |
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