CVE-2021-26073 - Broken authentication in Atlassian Connect Express (ACE)
Description
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. This is fixed in version 6.6.0.
Affected versions
3.0.2 - 6.5.0
Fixed versions
6.6.0 and later
Severity
This is an independent assessment and you should evaluate its applicability to your own IT environment.
CVSS v3 score: 9.1 => Critical severity
Exploitability Metrics
| Attack Vector | Network |
|---|---|
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
Scope Metric
| Scope | Changed |
|---|
Impact Metrics
| Confidentiality | High |
|---|---|
| Integrity | Low |
| Availability | Low |
https://asecurityteam.bitbucket.io/cvss_v3/#CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
What you need to do
Atlassian recommends that you upgrade to the latest version. Upgrade to atlassian-connect-express to 6.6.0 or higher.