Improper Neutralization of Special Elements Used in a Template Engine Affecting document-merge-service package, versions [0,]
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- published27 Sept 2026
- disclosed19 Aug 2026
- creditUnknown
Introduced: 19 Aug 2026
CVE-2026-53964 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
A fix was pushed into the master branch but not yet published.
Overview
document-merge-service is a Merge Document Template Service
Affected versions of this package are vulnerable to Improper Neutralization of Special Elements Used in a Template Engine in the processing of XLSX templates using a non-sandboxed Jinja environment. An attacker can execute arbitrary code on the server by supplying malicious template content. This is only exploitable if XLSX templates are enabled and processed by the service.
Workaround
This vulnerability can be mitigated by disabling the upload or usage of XLSX templates.