Double Free Affecting crossbeam package, versions <0.4.1



    Attack Complexity Low
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9.8 critical

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  • published 18 Dec 2018
  • disclosed 9 Dec 2018
  • credit c0gent

How to fix?

Upgrade crossbeam to version 0.4.1 or higher.


crossbeam is a package that provides a set of tools for concurrent programming.

Affected versions of this package are vulnerable to Double Free due to running element's destructor inside the epoch-based garbage collector.

Double free errors occur when free() is called more than once with the same memory address as an argument.


Calling free() twice on the same value can lead to memory leak. When a program calls free() twice with the same argument, the program's memory management data structures become corrupted and could allow a malicious user to write values in arbitrary memory spaces. This corruption can cause the program to crash or, in some circumstances, alter the execution flow. By overwriting particular registers or memory spaces, an attacker can trick the program into executing code of his/her own choosing, often resulting in an interactive shell with elevated permissions.