CVE-2026-63276
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
LibreOffice converts CFF fonts to Type 1 when subsetting a font, which occurs when exporting a document to PDF; CFF fonts may be embedded in documents. A stack buffer overflow exists in this conversion because converted operators are written into a fixed-size buffer without checking if they still fit. In fixed versions, the remaining capacity is tracked and conversion stops when it is used up.
Risk Assessment
Exporting a malicious document to PDF could trigger a stack buffer overflow, leading to a crash or potential code execution. This may result in remote code execution in the user's context.
Recommendation
Update LibreOffice to a version that includes the fix tracking remaining buffer capacity. Avoid exporting documents from untrusted sources to PDF.
Other vulnerabilities in LibreOffice
See all- CVE-2016-4324High
Use-after-free vulnerability in LibreOffice before 5.1.4 allows remote attackers to execute arbitrary code via a crafted RTF file, related to stylesheet and superscript tokens.
- CVE-2016-0795High
LibreOffice versions before 5.0.5 allow remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via a crafted LwpTocSuperLayout record in a LotusWordPro (lwp) document.
- CVE-2014-9093High
LibreOffice versions before 4.3.5 allow remote attackers to cause a denial of service (invalid write operation and crash) and possibly execute arbitrary code via a crafted RTF file.
- CVE-2014-0247High
LibreOffice version 4.2.4 automatically executes unspecified VBA macros, which may lead to unknown impacts and attack vectors.
- CVE-2017-8358Critical
LibreOffice before 2017-03-17 has an out-of-bounds write caused by a heap-based buffer overflow related to the ReadJPEG function in vcl/source/filter/jpeg/jpegc.cxx.
- CVE-2017-7882Critical
LibreOffice before March 14, 2017, has an out-of-bounds write related to the HWPFile::TagsRead function in hwpfilter/source/hwpfile.cxx.
- CVE-2017-7870Critical
LibreOffice before 2017-01-02 has an out-of-bounds write caused by a heap-based buffer overflow related to the tools::Polygon::Insert function in tools/source/generic/poly.cxx.
- CVE-2017-7856Critical
LibreOffice before 2017-03-11 has an out-of-bounds write caused by a heap-based buffer overflow in the SVMConverter::ImplConvertFromSVM1 function.
- CVE-2016-10327Critical
LibreOffice before December 22, 2016, has an out-of-bounds write caused by a heap-based buffer overflow related to the EnhWMFReader::ReadEnhWMF function in vcl/source/filter/wmf/enhwmf.cxx.
- CVE-2026-63279Medium
LibreOffice can import PICT images, which may be embedded in documents. An out-of-bounds read occurs when importing an image that uses a colour palette because the palette index is not checked against the number of entries. In fixed versions, the palette index is limited to the entries present.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS