What’s Vulnerable › Vulnerabilities
CVE-2026-63276: Stack buffer overflow in CFF to Type 1 font conversion
- Severity: medium (CVSS 5.4 v4.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-22 · updated 2026-09-22
- Weakness: CWE-787
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.
Affected products
- The Document Foundation LibreOffice: from 26.2 before < 26.2.5 — fixed in < 26.2.5
How to fix
Upgrade to a fixed version: The Document Foundation LibreOffice < 26.2.5. Check the vendor advisory for mitigations.
References
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