CVE-2021-25634

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.

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