CVE-2026-91778

Severity: high (CVSS 7.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-15 · updated 2026-09-16
Weakness: CWE-863

Description

In affected versions of Octopus Server, users with certain scoped permission sets could execute arbitrary scripts on a worker (including the Octopus Server built-in worker). Incorrect permission validation during script execution would allow the script to execute without the user possessing the required authorisation.

Affected products

Octopus Deploy Octopus Server: from 2019.0.0 before 2026.1.11725; from 2026.2.0 before 2026.2.13344; from 2026.3.0 before 2026.3.11816 — fixed in 2026.1.11725, 2026.2.13344, 2026.3.11816

How to fix

Upgrade to a fixed version: Octopus Deploy Octopus Server 2026.1.11725, 2026.2.13344, 2026.3.11816. Check the vendor advisory for mitigations.

References

https://advisories.octopus.com/post/2026/sa2026-08

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