Cyber Resilience

CVE-2021-26077

HighPublic PoC

Published: 10 May 2021

Published
10 May 2021
Modified
12 February 2025
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0039 60.3th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-26077 is a high-severity Improper Authentication (CWE-287) vulnerability in Atlassian Connect Spring Boot. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 39.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

atlassian
connect spring boot
1.1.0 — 2.1.3 · 2.1.4 — 2.1.5

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-287

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

addresses: CWE-287

Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.

addresses: CWE-287

Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.

References