CVE-2021-26077: Atlassian Connect Spring Boot

High severity, CVSS 8.8. EPSS: 1% chance of exploitation in the next 30 days.

Broken Authentication in Atlassian Connect Spring Boot (ACSB) in version 1.1.0 before 2.1.3 and from version 2.1.4 before 2.1.5: Atlassian Connect Spring Boot is a Java Spring Boot package for building Atlassian Connect apps. Authentication between Atlassian products and the Atlassian Connect Spring Boot app occurs with a server-to-server JWT or a context JWT. Atlassian Connect Spring Boot versions 1.1.0 before 2.1.3 and versions 2.1.4 before 2.1.5 erroneously accept context JWTs in lifecycle endpoints (such as installation) where only server-to-server JWTs should be accepted, permitting an attacker to send authenticated re-installation events to an app.

Affected products

• Atlassian Connect Spring Boot: from 1.1.0, before 2.1.3 (fixed in 2.1.3); from 2.1.4, before 2.1.5 (fixed in 2.1.5)

Published 2021-05-10. Last modified 2026-06-17.