How severe is CVE-2026-5268?

CVE-2026-5268 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-5268 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-5268?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-5268 published?

CVE-2026-5268 was published on 2026-07-06 and last updated on 2026-07-08.

CVE-2026-5268

CVE-2026-5268 is a critical-severity vulnerability with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-288.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-288
Published: 2026-07-06
Last modified: 2026-07-08

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-5268?: CVE-2026-5268 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-5268 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-5268?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-5268 published?: CVE-2026-5268 was published on 2026-07-06 and last updated on 2026-07-08.

References

https://www.ciena.com/product-security

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