Security readout for executives and security teams
Plain-English summary
This flaw affects Atlassian Connect apps built with vulnerable Atlassian Connect Spring Boot versions. The app may trust the wrong kind of JWT on lifecycle endpoints, allowing an attacker with some privileges to trigger authenticated re-installation events. The main business risk is unauthorized integrity changes to app installation state, not known data theft or service outage.
Executive priority
Treat this as a targeted integrity risk for Atlassian Connect applications. Prioritize teams operating custom Atlassian apps or marketplace apps built on ACSB, but do not treat it as critical without evidence of exposure or active exploitation.
Technical view
ACSB versions 1.1.0 before 2.1.3 accept context JWTs on lifecycle endpoints where only server-to-server JWTs should be valid. That breaks authentication boundaries for Atlassian Connect lifecycle handling and can permit authenticated re-installation events. CVSS 3.1 is 6.5 with high integrity impact, low attack complexity, and required low privileges.
Likely exposure
Exposure is most likely in custom or marketplace Atlassian Connect apps using ACSB 1.1.0 through versions before 2.1.3, especially apps exposing installation or lifecycle endpoints.
Exploitation context
The bundle does not cite active exploitation, and CISA KEV status is false. Public sources describe authentication bypass behavior involving context JWT acceptance, but they do not establish widespread exploitation or provide evidence of commodity attack use.
Researcher notes
The issue is a JWT-type validation failure mapped to CWE-287. The CVSS vector indicates network reachability, low complexity, low privileges, no user interaction, unchanged scope, no confidentiality impact, high integrity impact, and no availability impact. Sources describe lifecycle re-installation abuse, not remote code execution.
Mitigation direction
- Upgrade Atlassian Connect Spring Boot to version 2.1.3 or later.
- Identify all Atlassian Connect apps using ACSB in the affected version range.
- Review Atlassian’s advisory and developer guidance before deploying changes.
- Ensure lifecycle endpoints require server-to-server JWTs, not context JWTs.
- Review recent app installation and re-installation events for unexpected activity.
Validation and detection
- Inventory dependency manifests for Atlassian Connect Spring Boot versions.
- Confirm no deployed app uses ACSB 1.1.0 through versions before 2.1.3.
- Verify lifecycle endpoint tests reject context JWT authentication.
- Review logs for unusual installation or re-installation lifecycle events.
- Confirm remediation with vendor guidance and release documentation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-287: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-26074 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://confluence.atlassian.com/pages/viewpage.action?pageId=1051986106CVE reference · x_refsource_MISC
- https://community.developer.atlassian.com/t/action-required-atlassian-connect-vulnerability-allows-bypass-of-app-qsh-verification-via-context-jwts/47072CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authentication
Improper Authentication represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.