CVE-2026-63276 Details
Description
LibreOffice converts CFF fonts to Type 1 when it subsets a font, which happens when a document is exported to PDF, and CFF fonts may be embedded in documents. A stack buffer overflow existed in that conversion. The converted operators were written into a fixed size buffer with no check that they still fit, so a glyph emitting many operators wrote past the end of the buffer. In fixed versions the remaining capacity is tracked and the conversion stops when it is used up.
A stack buffer overflow vulnerability has been identified in LibreOffice during the conversion of CFF fonts to Type 1 fonts when subsetting occurs, such as during PDF export. This vulnerability arises because the conversion process writes the operators into a fixed-size buffer without verifying if they fit, allowing glyphs that emit multiple operators to overflow the buffer. In versions that have addressed this issue, the conversion now tracks the remaining buffer capacity and halts when it is fully utilized.
Users are advised to upgrade to LibreOffice version 26.2.5 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 22, 2026CISA-ADP
Assessed Sep 22, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://www.libreoffice.org/about-us/security/advisories/cve-2026-63276 | [email protected] | AdvisoryBundleRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-787 | Out-of-bounds Write | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| LibreOffice | All versions |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 22, 2026 | CVE Modified | CISA-ADP |
| Sep 22, 2026 | New CVE Received | [email protected] |