CVE-2026-21584 in Bamboo Data Center
Summary
by MITRE • 08/19/2026
This High severity Improper Authorization vulnerability was introduced in versions 10.0.0, 10.1.0, 10.2.0, 11.0.0, 12.0.0, and 12.1.0 of Bamboo Data Center. This Improper Authorization vulnerability, with a CVSS Score of 7.6, allows an authenticated attacker to gain unintended access and can lead to the exposure of resources or functionality, possibly providing attackers with sensitive information or even execute arbitrary code. Atlassian recommends that Bamboo Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: * Bamboo Data Center 10.2: Upgrade to a release greater than or equal to 10.2.22 * Bamboo Data Center 12.1: Upgrade to a release greater than or equal to 12.1.10 See the release notes (https://confluence.atlassian.com/bambooreleases/bamboo-release-notes-1189793869.html). You can download the latest version of Bamboo Data Center from the download center (https://www.atlassian.com/software/bamboo/download-archives). This vulnerability was reported via our Penetration Testing program.
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Analysis
by VulDB Data Team • 08/19/2026
The identified security issue represents a critical Improper Authorization flaw within Atlassian Bamboo Data Center, specifically affecting versions 10.0.0 through 12.1.0. This vulnerability is classified as High severity with a CVSS score of 7.6, indicating that it poses a significant risk to the confidentiality and integrity of systems running these affected software releases. The core technical deficiency lies in the application's access control mechanisms, which fail to properly verify whether an authenticated user has the necessary permissions to perform specific actions or access certain resources. This lapse allows attackers who have already obtained valid credentials for any low-privileged account to bypass intended security restrictions and interact with functionality reserved for administrators or other privileged roles.
From a technical perspective, this flaw aligns closely with CWE-269, which describes Improper Privilege Management, where the software does not properly assign privileges to actors based on their authorization levels. Furthermore, in the context of the MITRE ATT&CK framework, this vulnerability facilitates lateral movement and privilege escalation tactics by allowing an attacker to leverage existing low-level access to gain higher-level control over the CI/CD pipeline infrastructure. The exploitation vector typically involves authenticated users manipulating API requests or web interface interactions that lack sufficient server-side validation checks for role-based access controls. By exploiting these gaps, attackers can execute commands with elevated privileges, effectively bypassing the principle of least privilege that is fundamental to secure system design.
The operational impact of this vulnerability extends beyond simple data exposure. While it certainly enables the unauthorized disclosure of sensitive information such as build logs, configuration files, and source code repositories hosted within Bamboo Data Center, the consequences are more severe due to the potential for arbitrary code execution. An attacker with escalated privileges can manipulate deployment pipelines, inject malicious scripts into build processes, or alter system configurations. This capability transforms a standard authentication-based breach into a full compromise of the continuous integration environment, potentially leading to supply chain attacks where compromised builds distribute malware to downstream systems and applications dependent on these CI/CD outputs.
To mitigate this risk, Atlassian has released patched versions for supported release lines. Organizations running Bamboo Data Center version 10.2 must upgrade to version 10.2.22 or any subsequent minor release within that branch. Similarly, users of the 12.1 series are advised to update immediately to version 12.1.10 or later. It is imperative for administrators to verify their current installation versions against these fixed releases and apply updates during scheduled maintenance windows to minimize disruption to ongoing build activities. For those unable to upgrade immediately due to compatibility constraints, implementing strict network segmentation and enforcing multi-factor authentication on all Bamboo accounts can provide additional layers of defense by reducing the likelihood of credential compromise that precedes exploitation of this authorization flaw.
Security teams should also conduct a thorough audit of user permissions within their Bamboo instances to ensure that no unnecessary administrative privileges are assigned to standard developer or tester accounts. Regular review of access control lists and monitoring for anomalous privilege escalation attempts can help detect potential exploitation activities early. Additionally, keeping all dependent components up to date and reviewing the release notes linked in official advisories ensures awareness of related security fixes. The vulnerability was discovered through responsible disclosure via a penetration testing program, highlighting the importance of proactive security assessments in identifying logic-based flaws that automated scanners might overlook due to their reliance on authenticated sessions for exploitation.