Title: CVE-2019-9853 Insufficient URL decoding flaw in categorizing macro location

Announced: September 27, 2019

Fixed in: 6.2.6/6.3.1


LibreOffice documents can contain macros. The execution of those macros is controlled by the document security settings, typically execution of macros are blocked by default.

A URL decoding flaw existed in how the urls to the macros within the document were processed and categorized, resulting in the possibility to construct a document where macro execution bypassed the security settings.

The documents were correctly detected as containing macros, and prompted the user to their existence within the documents, but macros within the document were subsequently not controlled by the security settings allowing arbitrary macro execution

In the fixed versions, the parsed url describing the script location is correctly decoded before further processing.


Thanks to Nils Emmerich of ERNW Research GmbH for discovering and reporting this issue