Full Report
Atlassian security advisory (AV26-731)
Analysis Summary
# Vulnerability: Atlassian July 2026 Security Bulletin (Multiple Products)
## CVE Details
*Note: Due to the high number of vulnerabilities addressed in this monthly bulletin, the following focus on the highest-rated critical flaws.*
- **CVE ID:** CVE-2026-30247 (and others including CVE-2026-30248)
- **CVSS Score:** 9.8 (Critical)
- **CWE:** CWE-502 (Deserialization of Untrusted Data) / CWE-77 (Command Injection)
## Affected Systems
- **Products & Versions:**
- **Bamboo Data Center and Server:** Multiple versions prior to 9.6.0
- **Bitbucket Data Center and Server:** Multiple versions prior to 8.19.0
- **Confluence Data Center and Server:** Multiple versions prior to 8.5.4 (LTS)
- **Crowd Data Center and Server:** Multiple versions prior to 5.2.0
- **Fisheye/Crucible:** Versions 4.9.0 to 4.9.11
- **Jira / Jira Service Management:** Multiple versions including 9.12.0
- **Sourcetree (Mac & Windows):** Versions 3.4.11 to 3.4.12
## Vulnerability Description
The primary critical vulnerabilities addressed in this advisory involve insecure deserialization and command injection flaws within common Atlassian core components. These vulnerabilities allow an unauthenticated attacker to execute arbitrary code on the host operating system by sending specially crafted requests to the application. In the case of Sourcetree, the vulnerabilities typically involve argument injection via maliciously crafted repository URLs (protocol handler exploitation).
## Exploitation
- **Status:** Proof-of-Concept (PoC) available for certain components; no active exploitation in the wild confirmed at time of advisory.
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** High (Full data access)
- **Integrity:** High (System modification)
- **Availability:** High (System takeover/Denial of Service)
## Remediation
### Patches
Atlassian recommends upgrading to the latest Fixed Term Support or Long Term Support (LTS) versions:
- **Bamboo:** Upgrade to version 9.6.5 or higher.
- **Bitbucket:** Upgrade to version 8.19.1 or higher.
- **Confluence:** Upgrade to 8.5.5 (LTS) or 8.8.0.
- **Jira:** Upgrade to 9.12.2 (LTS) or higher.
- **Sourcetree:** Upgrade to version 3.4.13 or higher.
### Workarounds
- **Network Segmentation:** Restrict access to affected instances to trusted IP ranges/VPNs only.
- **Protocol Handler Disabling:** For Sourcetree, avoid clicking "Clone in Sourcetree" links from untrusted web sources until patched.
## Detection
- **Indicators of Compromise:** Look for unusual child processes spawned by the Java application (e.g., `sh`, `cmd.exe`, `whoami`) in system logs.
- **Log Analysis:** Monitor `atlassian-confluence.log` or `atlassian-jira.log` for unexpected stack traces involving `java.io.ObjectInputStream`.
## References
- Atlassian Security Bulletin July 2026: hxxps[://]confluence[.]atlassian[.]com/spaces/SECURITY/pages/1821999345/Security+Bulletin+-+July+21+2026
- Atlassian Trust Center: hxxps[://]www[.]atlassian[.]com/trust/security/advisories
- Canadian Centre for Cyber Security Advisory (AV26-731): hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/atlassian-security-advisory-av26-731