Prevent circumvention via specially crafted serialized string #17
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According to upstream sources a sign (`+`, `-`) is accepted before the length: https://github.com/php/php-src/blob/PHP-5.4.45/ext/standard/var_unserializer.re#L260-L266 So it is possible to circumvent the polyfill by manually adding it, i.e.: `O:9:"Exception"` vs `O:+9:"Exception"`
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According to upstream sources a sign (
+,-) is accepted before the length: https://github.com/php/php-src/blob/PHP-5.4.45/ext/standard/var_unserializer.re#L260-L266So it is possible to circumvent the polyfill by manually adding it, i.e.:
O:9:"Exception"vsO:+9:"Exception"