orca.securityadvisory

Orca: CVE-2026-45034 PhpSpreadsheet RCE Patch Bypass

Orca Security details CVE-2026-45034 (CVSS 9.8), a bypass of PhpSpreadsheet's File::prohibitWrappers() protection that was originally added to fix CVE-2026-34084. A crafted path with three or more slashes after the scheme (e.g. phar:///path/exploit.phar/dummy.csv) causes PHP's parse_url() to return false instead of a scheme string, skipping the is_string($scheme) check while PHP's stream layer still treats the path as a phar wrapper, enabling automatic phar deserialization via IOFactory::load() and full RCE on PHP 7.x (file-read primitive on PHP 8.x, with RCE restored if Phar::getMetadata() is later called). All 1.x versions through 1.30.4 are affected; PhpSpreadsheet 1.30.5 patches the issue, and the post recommends replacing parse_url()-based checks with str_contains($filename, '://') validation.