CVE-2026-59932 PhpSpreadsheet: Gnumeric reader unbounded gzip expansion causes memory exhaustion

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2.4.6, 2.0.0 through 2.1.17, and all releases up to and including 1.30.5, the Gnumeric reader reads attacker-supplied .gnumeric files into memory an...

CVE-2026-59932

CVE-2026-59932 concerns PhpSpreadsheet’s Gnumeric reader. The issue arises when reading attacker-supplied .gnumeric files: if the file starts with gzip magic bytes, the reader decodes the full compressed content via gzdecode() without a decompressed-size cap, which can cause memory exhaustion and...