CVE-2021-25634: Debian Linux

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to modify a digitally signed ODF document to insert an additional signing time timestamp which LibreOffice would incorrectly present as a valid signature signed at the bogus signing time. This issue affects: The Document Foundation LibreOffice 7-0 versions prior to 7.0.6; 7-1 versions prior to 7.1.2.

Affected products

• Debian Debian Linux: version 11.0 only
• Libreoffice Libreoffice: from 7.0.0, before 7.0.6 (fixed in 7.0.6); from 7.1.0, before 7.1.2 (fixed in 7.1.2)

Published 2021-10-12. Last modified 2026-06-17.