PatchSiren cyber security CVE debrief

CVE-2026-8358 The Document Foundation CVE debrief

CVE-2026-8358 is a medium-severity vulnerability in LibreOffice Calc that can lead to a heap buffer overflow when importing tracked changes from a spreadsheet. The vulnerability occurs when a document reuses the same change identifier for two different kinds of change, causing the importer to treat one change object as a different, larger type and write past the end of its allocation. In fixed versions, records with a duplicate identifier are rejected.

Vendor: The Document Foundation
Product: LibreOffice
CVSS: MEDIUM 5.4
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-15
Original CVE updated: 2026-06-15
Advisory published: 2026-06-15
Advisory updated: 2026-06-15

Who should care

Users of LibreOffice Calc, particularly those who import tracked changes from spreadsheet documents, should be aware of this vulnerability and ensure they are using a fixed version.

Technical summary

The vulnerability is caused by a heap buffer overflow in the LibreOffice Calc importer. When a document reuses the same change identifier for two different kinds of change, the importer incorrectly treats one change object as a different, larger type and writes past the end of its allocation.

Defensive priority

Medium

Recommended defensive actions

Update to a fixed version of LibreOffice Calc
Be cautious when importing tracked changes from spreadsheet documents

Evidence notes

The CVE record was obtained from the official CVE website and the NVD detail page.

Official resources

CVE-2026-8358 was published on 2026-06-15T18:16:37.630Z and has not been modified since then.