{"id":"CVE-2026-53964","title":"Document Merge Service is a document template merge service providing an API to manage templates and merge them with given data","summary":"Document Merge Service is a document template merge service providing an API to manage templates and merge them with given data. Prior to version 9.1.0, a remote code execution (RCE) via server-side template injection (SSTI) allows for u…","severity":"high","cvss":7.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-1336"],"vendor":"adfinis","product":"document-merge-service","affected":["document-merge-service < 9.1.0"],"patched":["document-merge-service 9.1.0"],"published":"2026-10-01","updated":"2026-10-02","sourceUpdated":"2026-10-02T18:47:49.947","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53964","references":[{"url":"https://github.com/adfinis/document-merge-service/releases/tag/v9.1.0","label":"security-advisories@github.com"},{"url":"https://github.com/adfinis/document-merge-service/security/advisories/GHSA-w47q-945m-q9pc","label":"security-advisories@github.com"},{"url":"https://github.com/adfinis/document-merge-service"},{"url":"https://pypi.org/project/document-merge-service"},{"url":"https://github.com/advisories/GHSA-w47q-945m-q9pc"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53964"}],"tags":["nvd","cve.org","osv","pip","ghsa"],"epss":0.00493,"epssPercentile":0.42113,"aliases":["GHSA-w47q-945m-q9pc","PYSEC-2026-3830"],"ecosystem":"pip","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-01T20:12:41.561346Z"},"ingestedAt":"2026-08-19T19:44:03.129Z","slug":"CVE-2026-53964","body":"## Overview\n\nDocument Merge Service is a document template merge service providing an API to manage templates and merge them with given data. Prior to version 9.1.0, 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. This issue has been patched in version 9.1.0.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-53964)\n\nAffected packages:\n\n- `document-merge-service < 9.1.0`\n\nPatched in:\n\n- `document-merge-service 9.1.0`\n\nSource: https://osv.dev/vulnerability/GHSA-w47q-945m-q9pc","depth":"twilight","depthScore":40,"depthScoreParts":{"impact":39.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}