PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service

影響: composer:phpoffice/phpspreadsheet >= 4.0.0, <= 5.9.0 → 5.10.0, composer:phpoffice/phpspreadsheet >= 3.3.0, <= 3.10.7 → 3.10.8

The SpreadsheetML XML reader (Reader\Xml) scans file content twice through XmlScanner::scan(), and each scan runs an unentity() callback that calls html_entity_decode() after the pattern check. By double-encoding the toUtf8($xml); if (preg_match($pattern, $xml)) { // CHECK 2 (UTF-8) throw new Exception('Detected use of ENTITY...'); } if ($this->callback !== null) { $xml = call_user_func($this->callback, $xml); // DECODE (after checks!) } return $xml; // getSecurityScannerOrThrow()->scan($data);…

GitHub Advisory Databaseで読む

2026/10/28 00:38、GitHub Advisory Databaseが「PhpSpreadsheet: XmlScanner Bypass via Double-Encoded unentity() TOCTOU Allows XXE and Denial of Service」を公開しました (種別: 脆弱性アドバイザリ)。重大度は「重要」(high) です。関連する技術: PHP。CVE: CVE-2026-108357。