The phar_make_dirstream function in ext/phar/dirstream.c in PHP before 5.6.18 and 7.x before 7.0.3 mishandles zero-size ././@LongLink files, which allows remote attackers to cause a denial of service (uninitialized pointer dereference) or possibly have unspecified other impact via a crafted TAR archive.
The product accesses or uses a pointer that has not been initialized.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Php | Php | * | 5.5.36 (excluding) |
| Php | Php | 5.6.0 (including) | 5.6.18 (excluding) |
| Php | Php | 7.0.0 (including) | 7.0.3 (excluding) |
If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the product to read from or write to unexpected memory locations, leading to a denial of service. If the uninitialized pointer is used as a function call, then arbitrary functions could be invoked. If an attacker can influence the portion of uninitialized memory that is contained in the pointer, this weakness could be leveraged to execute code or perform other attacks. Depending on memory layout, associated memory management behaviors, and product operation, the attacker might be able to influence the contents of the uninitialized pointer, thus gaining more fine-grained control of the memory location to be accessed.