LibreOffice and Apache OpenOffice Flaws Enable Remote Code Execution via Malicious Spreadsheets Without Macro Warnings
Two vulnerabilities, CVE-2026-63277 in LibreOffice Calc and CVE-2026-59265 in Apache OpenOffice, allow attackers to execute arbitrary code simply by tricking users into opening specially crafted spreadsheet files. The flaws exploit Java integration and class path handling, bypassing traditional macro security prompts entirely. LibreOffice has already released fixes in versions 26.2.5 and 26.8.0 that restrict class path entries to local file URLs only. Apache OpenOffice 4.1.16 and earlier remain vulnerable, with the stable patch expected in 4.1.17; interim mitigation requires disabling Java integration. The issues highlight risks in office suites that process untrusted documents containing external data connections or JDBC references. Organizations are advised to enforce least-privilege execution and avoid opening files from unknown sources until patches are applied.
HispasecOct 6, 2026Translated from Spanish