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CERT Coordination Center

Atlassian Bitbucket on Windows is vulnerable to privilege escalation due to weak ACLs

Vulnerability Note VU#240785

Original Release Date: 2021-02-18 | Last Revised: 2021-02-18


Atlassian Bitbucket on Windows fails to properly set ACLs, which can allow an unprivileged Windows user to run arbitrary code with SYSTEM privileges.


The Atlassian Bitbucket Windows installer fails to set a secure access-control list (ACL) on the default installation directory, such as C:\Atlassian\Bitbucket\. By default, unprivileged users can create files in this directory structure, which creates a privilege-escalation vulnerability.


By placing a specially-crafted DLL file in the Bitbucket installation directory, an unprivileged user may be able to execute arbitrary code with SYSTEM privileges on a Windows system with the vulnerable Bitbucket software installed. See DLL Search Order Hijacking for more details.


Apply an update

This issue has been addressed in the Bitbucket Windows installer for versions 7.10.1, 7.6.4, and 6.10.9. Please see for more details.


This vulnerability was reported by Will Dormann of the CERT/CC.

This document was written by Will Dormann.

Vendor Information


Atlassian Affected

Notified:  2020-11-24 Updated: 2021-02-18

Statement Date:   February 01, 2021

CVE-2020-36233 Affected

Vendor Statement

We have not received a statement from the vendor.


Other Information

CVE IDs: CVE-2020-36233
Date Public: 2021-02-18
Date First Published: 2021-02-18
Date Last Updated: 2021-02-18 18:01 UTC
Document Revision: 1

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