CVE-2021-26077 in the critical feed json
Improper Authentication in Atlassian Connect Spring Boot
published 2021-05-09 5 y ago modified 2026-06-17 4 mo ago also GHSA-2x7v-w2mv-f3rx , EUVD-2021-1244
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 61%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- maven com.atlassian.connect:atlassian-connect-spring-boot 2.1.3, 2.1.5
- Atlassian Atlassian Connect Spring Boot (ACSB) 2.1.3, 2.1.5
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 20 mo ago
Exploit prediction
0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- community.developer.atlassian.com https://community.developer.atlassian.com/t/action-required-atlassian-connect-vulnerability-allows-bypass-of-app-qsh-verification-via-context-jwts/47072 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L |
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
| GitHub | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| maven | com.atlassian.connect:atlassian-connect-spring-boot | >=1.1.0, <2.1.3 >=2.1.4, <2.1.5 |
2.1.3 2.1.5 |
Affected products
- Atlassian Atlassian Connect Spring Boot (ACSB)
Classification
- Weakness
-
- CWE-287 Improper Authentication
- Technology feeds
References
-
community.developer.atlassian.com
/t/action-required-atlassian-connect-vulnerability-allows-bypass-of-app-qsh-verification-via-context-jwts/4707
web, exploit, issue-tracking, vendor-advisory
-
confluence.atlassian.com
/pages/viewpage.action?pageId=1063555147
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-26077
advisory
Sources
- CVE List CVE-2021-26077
- GitHub Advisory GHSA-2x7v-w2mv-f3rx
- NVD CVE-2021-26077
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.