CVE-2026-53964
Document Merge Service vulnerable to RCE via SSTI (xlsx tempaltes)
Summary
### Impact 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. The vulnerability is limited to XLSX templates, were the `xltpl` library uses a npn-sandboxed Jinja environment for the processing of the template. ### Patches It has been patched in [v9.1.0](https://github.com/adfinis/document-merge-service/releases/tag/v9.1.0) ### Workarounds Disable the upload/usage of XLSX templates. ### 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
Affected packages
| Ecosystem | Package | Affected versions | Fixed versions |
|---|---|---|---|
| PyPI | document-merge-service | — | 9.1.0 |
Remediation: Upgrade to 9.1.0 or later.
References
Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.
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