What’s Vulnerable › Vulnerabilities

CVE-2021-25634: Timestamp Manipulation with Signature Wrapping

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-12 · updated 2026-06-17
• Weakness: CWE-295

Description

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 Linux: 11.0
• The Document Foundation LibreOffice: from 7.0.0 before 7.0.6; from 7.1.0 before 7.1.2 — fixed in 7.0.6, 7.1.2

How to fix

Upgrade to a fixed version: The Document Foundation LibreOffice 7.0.6, 7.1.2. Check the vendor advisory for mitigations.

References

• https://www.debian.org/security/2021/dsa-4988
• https://www.libreoffice.org/about-us/security/advisories/CVE-2021-25634
• https://www.debian.org/security/2021/dsa-4988
• https://www.libreoffice.org/about-us/security/advisories/CVE-2021-25634

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