What is CVE-2026-53964?

CVE-2026-53964 is a high-severity vulnerability in Adfinis Document-Merge-Service, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 7.2/10. Published 2026-10-01.

How severe is CVE-2026-53964?

High severity. CVSS v3 base score is 7.2 out of 10.

Vulnerability in Adfinis Document-Merge-Service

CVE-2026-53964

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 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.

Published 2026-10-01 · last modified 2026-10-01.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Adfinis Document-Merge-Service — versions < 9.1.0

Weakness classification (CWE)

CWE-1336 — Improper Neutralization of Special Elements Used in a Template Engine

References

Frequently asked questions

What is CVE-2026-53964?: CVE-2026-53964 is a high-severity vulnerability in Adfinis Document-Merge-Service, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 7.2/10. Published 2026-10-01.
How severe is CVE-2026-53964?: High severity. CVSS v3 base score is 7.2 out of 10.