GHSA-2MRG-GJXQ-2GVR PHPSpreadsheet: Gnumeric reader unbounded gzip expansion causes memory exhaustion

Summary PhpSpreadsheet's Gnumeric reader reads attacker-supplied .gnumeric files into memory and, when the file starts with gzip magic bytes, calls gzdecode on the full compressed contents without enforcing a decompressed-size limit. A very small compressed .gnumeric file can expand to data large...