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High [CVE-2021-26073] Broken Authentication in Atlassian Connect Express (ACE) from version 3.0.2 before version 6.6.0: Atlassian Connect Express is a…

This high-severity Atlassian advisory covers CVE-2021-26073.

CVE-2021-26073 Published Apr 16, 2021Updated by vendor Jun 17, 2026
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AtlassianUnclassified
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Summary

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 from 3.0.2 before 6.6.0 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.

Affected versions
  • 3.0.2

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions
  • 6.6.0

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation

Upgrade to a fixed release: 6.6.0. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

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