{"id":"CVE-2026-53964","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-53964","summary":"Document Merge Service vulnerable to RCE via SSTI (xlsx tempaltes)","details":"### Impact\nA 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. \n\n### Patches\nIt has been patched in [v9.1.0](https://github.com/adfinis/document-merge-service/releases/tag/v9.1.0)\n\n### Workarounds\nDisable the upload/usage of XLSX templates.\n\n### References\nAre there any links users can visit to find out more?\n\nhttps://book.hacktricks.xyz/pentesting-web/ssti-server-side-template-injection/jinja2-ssti","published":"2026-08-19T19:17:19Z","modified":"2026-08-19T19:30:06.744295176Z","cvss":{"score":7.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"document-merge-service","fixedVersion":"9.1.0"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/adfinis/document-merge-service/security/advisories/GHSA-w47q-945m-q9pc"},{"type":"PACKAGE","url":"https://github.com/adfinis/document-merge-service"},{"type":"WEB","url":"https://github.com/adfinis/document-merge-service/releases/tag/v9.1.0"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-19T19:30:06.744295176Z"}}