CVE-2021-31819: Octopus Halibut

Critical severity, CVSS 9.8. EPSS: 2.4% chance of exploitation in the next 30 days.

In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already trust each other based on certificate verification.

Affected products

• Octopus Halibut: before 4.4.7 (fixed in 4.4.7)

Published 2021-09-22. Last modified 2026-06-17.