LibreOffice supports the storage of passwords for web connections in the user’s configuration database. The stored passwords are encrypted with a single master key provided by the user. A flaw in LibreOffice existed where master key was poorly encoded resulting in weakening its entropy from 128 to 43 bits making the stored passwords vulerable to a brute force attack if an attacker has access to the users stored config. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.7; 7.3 versions prior to 7.3.3.

LibreOffice supports the storage of passwords for web connections in the user’s configuration database. The stored passwords are encrypted with a single master key provided by the user. A flaw in LibreOffice existed where the required initialization vector for encryption was always the same which weakens the security of the encryption making them vulnerable if an attacker has access to the user's configuration data. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.7; 7.3 versions prior to 7.3.1.

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 create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.5.

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.

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 create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to combine multiple certificate data, which when opened caused LibreOffice to display a validly signed indicator but whose content was unrelated to the signature shown. This issue affects: The Document Foundation LibreOffice 7-0 versions prior to 7.0.6; 7-1 versions prior to 7.1.2.

In the LibreOffice 7-1 series in versions prior to 7.1.2, and in the 7-0 series in versions prior to 7.0.5, the denylist can be circumvented by manipulating the link so it doesn't match the denylist but results in ShellExecute attempting to launch an executable type.

The Portable Document Format (PDF) specification does not provide any information regarding the concrete procedure of how to validate signatures. Consequently, an Incremental Saving vulnerability exists in multiple products. When an attacker uses the Incremental Saving feature to add pages or annotations, Body Updates are displayed to the user without any action by the signature-validation logic. This affects Foxit Reader before 9.4 and PhantomPDF before 8.3.9 and 9.x before 9.4. It also affects LibreOffice, Master PDF Editor, Nitro Pro, Nitro Reader, Nuance Power PDF Standard, PDF Editor 6 Pro, PDFelement6 Pro, PDF Studio Viewer 2018, PDF Studio Pro, Perfect PDF 10 Premium, and Perfect PDF Reader.

LibreOffice has a 'stealth mode' in which only documents from locations deemed 'trusted' are allowed to retrieve remote resources. This mode is not the default mode, but can be enabled by users who want to disable LibreOffice's ability to include remote resources within a document. A flaw existed where remote graphic links loaded from docx documents were omitted from this protection prior to version 6.4.4. This issue affects: The Document Foundation LibreOffice versions prior to 6.4.4.

ODF documents can contain forms to be filled out by the user. Similar to HTML forms, the contained form data can be submitted to a URI, for example, to an external web server. To create submittable forms, ODF implements the XForms W3C standard, which allows data to be submitted without the need for macros or other active scripting Prior to version 6.4.4 LibreOffice allowed forms to be submitted to any URI, including file: URIs, enabling form submissions to overwrite local files. User-interaction is required to submit the form, but to avoid the possibility of malicious documents engineered to maximize the possibility of inadvertent user submission this feature has now been limited to http[s] URIs, removing the possibility to overwrite local files. This issue affects: The Document Foundation LibreOffice versions prior to 6.4.4.

If LibreOffice has an encrypted document open and crashes, that document is auto-saved encrypted. On restart, LibreOffice offers to restore the document and prompts for the password to decrypt it. If the recovery is successful, and if the file format of the recovered document was not LibreOffice's default ODF file format, then affected versions of LibreOffice default that subsequent saves of the document are unencrypted. This may lead to a user accidentally saving a MSOffice file format document unencrypted while believing it to be encrypted. This issue affects: LibreOffice 6-3 series versions prior to 6.3.6; 6-4 series versions prior to 6.4.3.