PatchSiren cyber security CVE debrief

CVE-2026-6045 The Document Foundation CVE debrief

A heap buffer overflow existed in LibreOffice when importing an EMF+ gradient brush. The number of gradient blend points was read from the file and used to compute an allocation size, but that multiplication could overflow, so a small buffer was allocated and then filled as if it were large, writing past its end. In fixed versions, the blend-point count is checked against the data actually available before allocating.

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 who open documents containing EMF+ graphics may be affected by this vulnerability.

Technical summary

The vulnerability occurs when importing an EMF+ gradient brush. The number of gradient blend points is read from the file and used to compute an allocation size. However, the multiplication can overflow, resulting in a small buffer being allocated and then filled as if it were large, leading to a heap buffer overflow.

Defensive priority

MEDIUM

Recommended defensive actions

Update LibreOffice to a fixed version.
Be cautious when opening documents from untrusted sources that contain EMF+ graphics.

Evidence notes

The CVE record indicates that the vulnerability has a CVSS score of 5.4 and a severity of MEDIUM.

Official resources

CVE-2026-6045 was published on 2026-06-15T18:16:37.007Z.