Atlassian: Critical Bamboo Data Center and Server Vulnerability Enables Command Injection Attacks

Critical OS Command Injection Flaw in Atlassian Bamboo Puts CI/CD Pipelines at Risk

Atlassian disclosed a critical security vulnerability (CVE-2026-21571) in Bamboo Data Center and Server, allowing remote attackers to execute arbitrary operating system commands. The flaw, assigned a CVSS score of 9.4, was published on April 21, 2026, as part of Atlassian’s monthly Security Bulletin.

The vulnerability affects multiple versions of Bamboo, including 9.6.0, 10.0.0, 10.1.0, 10.2.0, 11.0.0, 11.1.0, 12.0.0, and 12.1.0. It stems from a third-party dependency but remains classified as critical due to its potential impact. Exploitation requires low-level authentication and no user interaction, making it a high-risk threat for enterprise environments.

Successful attacks could enable threat actors to inject malicious code into CI/CD pipelines, compromising software supply chains, accessing sensitive data, or disrupting system operations. Given Bamboo’s role in automating build and deployment workflows, unpatched systems pose a significant risk to development environments.

Atlassian has released patched versions (12.1.6 (LTS), 10.2.18 (LTS), and 9.6.25) to mitigate the flaw. Organizations unable to upgrade immediately are advised to review Atlassian’s Vulnerability Disclosure Portal for mitigation steps, including monitoring authentication logs and auditing CI/CD pipelines for unauthorized changes.

The April 2026 Security Bulletin also addressed 37 additional vulnerabilities, including a CVSS 10.0 cross-site scripting flaw and a remote code execution issue in other Atlassian products like Jira, Confluence, and Bitbucket.

Source: https://cyberpress.org/critical-bamboo-data-center-and-server-vulnerability-enables-command-injection-attacks/

Atlassian cybersecurity rating report: https://www.rankiteo.com/company/atlassian

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"linkid": "atlassian",
"type": "Vulnerability",
"date": "4/2026",
"severity": "100",
"impact": "5",
"explanation": "Attack threatening the organization's existence"

{'affected_entities': [{'industry': 'Technology/Software Development',
                        'name': 'Atlassian Bamboo Data Center and Server',
                        'type': 'Software'}],
 'attack_vector': 'Remote',
 'data_breach': {'type_of_data_compromised': 'Sensitive data'},
 'date_publicly_disclosed': '2026-04-21',
 'description': 'Atlassian disclosed a critical security vulnerability '
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                'remote attackers to execute arbitrary operating system '
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                'published on April 21, 2026, as part of Atlassian’s monthly '
                'Security Bulletin. The vulnerability affects multiple '
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 'impact': {'data_compromised': 'Sensitive data',
            'operational_impact': 'Disruption of system operations',
            'systems_affected': 'CI/CD pipelines, Bamboo Data Center and '
                                'Server'},
 'post_incident_analysis': {'corrective_actions': 'Patches released; '
                                                  'monitoring and auditing '
                                                  'recommendations provided',
                            'root_causes': 'Third-party dependency '
                                           'vulnerability'},
 'recommendations': 'Upgrade to patched versions (12.1.6 (LTS), 10.2.18 (LTS), '
                    'or 9.6.25); monitor authentication logs; audit CI/CD '
                    'pipelines for unauthorized changes.',
 'references': [{'source': 'Atlassian Security Bulletin',
                 'url': 'https://example.com/atlassian-security-bulletin-april-2026'}],
 'response': {'containment_measures': 'Patches released (versions 12.1.6 '
                                      '(LTS), 10.2.18 (LTS), and 9.6.25)',
              'enhanced_monitoring': 'Monitoring authentication logs',
              'remediation_measures': 'Upgrade to patched versions; monitor '
                                      'authentication logs; audit CI/CD '
                                      'pipelines for unauthorized changes'},
 'title': 'Critical OS Command Injection Flaw in Atlassian Bamboo Puts CI/CD '
          'Pipelines at Risk',
 'type': 'OS Command Injection',
 'vulnerability_exploited': 'CVE-2026-21571'}