Stack buffer overflow in CFF to Type 1 font conversion (CVE-2026-63276) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-63276

Stack buffer overflow in CFF to Type 1 font conversion

Answer in brief

CVE-2026-63276 records a Unknown severity vulnerability in Stack buffer overflow in CFF to Type 1 font conversion. The current sources do not mark it as known exploited. The current feed maps The Document Foundation/LibreOffice (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps The Document Foundation/LibreOffice (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
The Document Foundation/LibreOfficegeneric	>=26.2 << 26.2.5	< 26.2.5

Recommended response

Check inventory. Check lockfiles and deployed manifests for The Document Foundation/LibreOffice.
Review the reported fix. Update The Document Foundation/LibreOffice to < 26.2.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Source referencelibreoffice.org

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.