Vulnerability in Ciena 6500 S-Series
CVE-2026-5268
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.007 (50.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Ciena 6500 S-Series — versions R16.96 and prior
- Ciena 6500 T-Series — versions R16.1 and prior
- Ciena Cpl — versions R12.63 and prior
- Ciena Pts — versions R16.1 and prior
Weakness classification (CWE)
References
- 7bd90cf1-1651-495e-9ae8-9415fb3c9feb (vendor-advisory)
Frequently asked questions
- What is CVE-2026-5268?
- CVE-2026-5268 is a critical-severity vulnerability in Ciena 6500 S-Series, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 9.1/10. Published 2026-07-06.
- How severe is CVE-2026-5268?
- Critical severity. CVSS v3 base score is 9.1 out of 10.