Race condition in the FastCopy optimization in the Array.Copy method in metadata/icall.c in Mono, when Moonlight 2.x before 2.4.1 or 3.x before 3.99.3 is used, allows remote attackers to trigger a buffer overflow and modify internal data structures, and cause a denial of service (plugin crash) or corrupt the internal state of the security manager, via a crafted media file in which a thread makes a change after a type check but before a copy action.

It was reported [1] that threads in Mono were not properly cleaned up upon finalization, so if one thread was resurrected, it would be possible to see the pointer to freed memory. This could lead to unintended information disclosure, and possibly a crash.

This has been corrected upstream [2].

[1] https://bugzilla.novell.com/showbug.cgi?id=678515 [2] https://github.com/mono/mono/commit/722f9890f09aadfc37ae479e7d946d5fc5ef7b91

Use-after-free vulnerability in Mono, when Moonlight 2.x before 2.4.1 or 3.x before 3.99.3 is used, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to finalizing and then resurrecting a DynamicMethod instance.

Use-after-free vulnerability in Mono, when Moonlight 2.x before 2.4.1 or 3.x before 3.99.3 is used, allows remote attackers to cause a denial of service (plugin crash) or obtain sensitive information via vectors related to member data in a resurrected MonoThread instance.