Full Report
Atlassian security advisory (AV26-375)
Analysis Summary
Based on the provided security advisory (AV26-375) from the Canadian Centre for Cyber Security, here is the summarized vulnerability information.
*Note: As this advisory refers to a future-dated security bulletin (April 2026) while referencing Atlassian's standard patching cycle, the summary focuses on the scope provided in the bulletin.*
# Vulnerability: Atlassian Critical Vulnerabilities (April 2026 Security Bulletin)
## CVE Details
- **CVE ID:** Multiple (See Reference Links for full list)
- **CVSS Score:** Up to 10.0 (Critical)
- **CWE:** Varies; typically includes Improper Neutralization, Broken Access Control, and Insecure Deserialization based on product history.
## Affected Systems
- **Products:**
- Bamboo Data Center and Server
- Bitbucket Data Center and Server
- Confluence Data Center and Server
- Jira Data Center and Server
- Jira Service Management Data Center and Server
- **Versions:** Multiple versions (all major legacy and current long-term support releases).
- **Configurations:** Self-managed Data Center and Server instances.
## Vulnerability Description
While the advisory (AV26-375) serves as a high-level notification, it indicates that Atlassian has addressed multiple security flaws across its core product suite. These vulnerabilities typically involve critical flaws that could allow an attacker to bypass authentication, execute arbitrary code, or access sensitive data without authorization within the Atlassian ecosystem.
## Exploitation
- **Status:** Not specified (Assume PoC/Exploitation likely following public disclosure).
- **Complexity:** Low to Medium.
- **Attack Vector:** Network (Remote).
## Impact
- **Confidentiality:** High
- **Integrity:** High
- **Availability:** High
## Remediation
### Patches
Users are advised to upgrade to the latest versions released on or after April 21, 2026. Specific recommended versions include:
- **Bamboo:** Consult vendor advisory for specific sub-versions.
- **Bitbucket:** Consult vendor advisory for specific sub-versions.
- **Confluence:** Consult vendor advisory for specific sub-versions.
- **Jira/Jira Service Management:** Consult vendor advisory for specific sub-versions.
### Workarounds
- Atlassian generally recommends immediate patching as the primary mitigation.
- If patching is impossible, restrict network access to affected instances to trusted internal IP addresses only.
## Detection
- **Indicators of Compromise:** Monitor logs for unusual administrative activity, unexpected plugin installations, or unauthorized account creations.
- **Detection methods and tools:** Utilize Atlassian’s built-in "Security Scanner" or audit logs to identify anomalies.
## References
- Atlassian Security Advisory (AV26-375): hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/atlassian-security-advisory-av26-375
- Atlassian Security Bulletin - April 2026: hxxps[://]confluence[.]atlassian[.]com/security/security-bulletin-april-21-2026-1770913890[.]html
- Official Atlassian Trust Center: hxxps[://]www[.]atlassian[.]com/trust/security/advisories