CVE-2021-25635 - CVE House

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Status published Medium CVE-2021-25635

Content Manipulation with Certificate Validation Attack

5.2 CVSS

Vulnerability Description

An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to self sign an ODF document, with a signature untrusted by the target, then modify it to change the signature algorithm to an invalid (or unknown to LibreOffice) algorithm and LibreOffice would incorrectly present such a signature with an unknown algorithm as a valid signature issued by a trusted person This issue affects LibreOffice: from 7.0 before 7.0.5, from 7.1 before 7.1.1.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

NDS of Ruhr University Bochum

References

https://www.libreoffice.org/about-us/security/advisories/cve-2021-25635/

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Affected Vendor

The Document Foundation

View all reports →

Affected Software

LibreOffice

Vulnerable Versions:

7.0, 7.1

Timeline

Official Publish: March 21st, 2025

Last Modified: March 21st, 2025

Added to House: July 21st, 2026

CVSS Vectors

Weaknesses (CWE)

MITRE ATT&CK TTPs

T1557 Adversary-in-the-Middle

Credential Access

T1040 Network Sniffing

T1552 Unsecured Credentials

Credential Access

T1071 Application Layer Protocol

Command and Control

T1565 Data Manipulation