URL Decoding Flaw in LibreOffice Macros Allows Bypass of Security Settings

CVE-2019-9853 · HIGH Severity

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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 This issue affects: LibreOffice 6.2 series versions prior to 6.2.7; LibreOffice 6.3 series versions prior to 6.3.1.

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