What is CVE-2026-4881?

CVE-2026-4881 is a medium-severity vulnerability in Octopus Octopus_server, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-06-04.

How severe is CVE-2026-4881?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Octopus Octopus_server

CVE-2026-4881

In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated user being able to make server level changes using a certain API endpoint despite receiving an error.

Vulnerability class: Broken Access Control

EPSS: 0.002 (11.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Octopus Octopus_server
Octopus Deploy Server — versions 2023.0.0, 2025.4.0, 2026.1.0

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

security@octopus.com (Vendor Advisory)

Frequently asked questions

What is CVE-2026-4881?: CVE-2026-4881 is a medium-severity vulnerability in Octopus Octopus_server, classified under Missing Authorization. CVSS score: 6.5/10. Published 2026-06-04.
How severe is CVE-2026-4881?: Medium severity. CVSS v3 base score is 6.5 out of 10.