Vulnerability · Published Jul 6, 2026 · Assigned by Ciena
CVE-2026-5268SFTP Server Authentication Weakness
Critical 9.1
In plain English
A critical-severity authentication bypass in 6500 S-Series from CIENA. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.7%top 48.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| 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 |
Weakness: CWE-288 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- https://www.ciena.com/product-security vendor-advisory