Broken Authentication in Atlassian Connect Express (ACE) from version 3.0.2 before version 6.6.0: Atlassian Connect Express is a Node.js package for building Atlassian Connect apps. Authentication between Atlassian products and the Atlassian Connect Express app occurs with a server-to-server JWT or a context JWT. Atlassian Connect Express versions between 3.0.2 - 6.5.0 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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-26073
• https://community.developer.atlassian.com/t/action-required-atlassian-connect-vulnerability-a[…]ypass-of-app-qsh-verification-via-context-jwts/47072
• https://confluence.atlassian.com/pages/viewpage.action?pageId=1051986099
• https://security.netapp.com/advisory/ntap-20210604-0004/