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Review reviewCritical

CVE-2026-5268

CIENA 6500 S-Series, 6500 T-Series, PTS

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.

CVSS
9.1
EPSS
0.42%
34.5% percentile
CISA KEV
Not listed
Published
2026.07.07
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.42%
Technical severityCVSS 9.1

Vulnerability overview

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 product and versions

Product
CIENA 6500 S-Series, 6500 T-Series, PTS
Affected versions
R16.96 and prior, R16.1 and prior, R12.63 and prior
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that CIENA 6500 S-Series, 6500 T-Series, PTS and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE
CWE-288
CVE-2026-5268 — CIENA 6500 S-Series, 6500 T-Series, PTS | SECUFOCUS NOW