Prevent circumvention via specially crafted serialized string #17

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huncrys wants to merge 1 commit into dbrumann:2.x from huncrys:patch-1

huncrys commented Mar 12, 2025

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"


          Prevent circumvention via specially crafted serialized string

7cbbc66

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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