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where the integer expression size and the declaration of vla are both evaluated at runtime. If the size argument supplied to a variable length array is not a positive integer value, the behavior is undefined. (See undefined behavior 7572.) Additionally, if the magnitude of the argument is excessive, the program may behave in an unexpected way. An attacker may be able to leverage this behavior to overwrite critical program data [Griffiths 2006]. The programmer must ensure that size arguments to variable length arrays, especially those derived from untrusted data, are in a valid range.
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