CVE-2021-26074: Broken Authentication in Atlassian Connect Spring Boot (ACSB) from version 1.1.0 before version 2.1.3: Atlassian Connect Spring Boot is a Java Spring ...

Description

Broken Authentication in Atlassian Connect Spring Boot (ACSB) from version 1.1.0 before version 2.1.3: 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 from version 1.1.0 before version 2.1.3 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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.65%

46.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Atlassian	Connect Spring Boot	>= 1.1.0, < 2.1.3

References

Timeline

Published: Apr 16, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26074?

Broken Authentication in Atlassian Connect Spring Boot (ACSB) from version 1.1.0 before version 2.1.3: 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 from version 1.1.0 before version 2.1.3 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.

How severe is CVE-2021-26074?

CVE-2021-26074 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.65% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26074?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.