FreeBSD Security Advisory FreeBSD-SA-03:16.filedesc - A programming error in the readv system call can result in the given file descriptor's reference count being erroneously incremented. A local attacker may cause the operating system to crash by repeatedly calling readv on a file descriptor until the reference count wraps to a negative value, and then calling close on that file descriptor. Similarly, it may be possible to cause a file descriptor to reference unallocated kernel memory, but remain valid. If a new file is later opened and the kernel allocates the new file structure at the same memory location, then an attacker may be able to gain read or write access to that file. This may in turn lead to privilege escalation. This affects releases 4.3-RELEASE through 4.8 RELEASE.
d77bc848ba499127eb6972feeba3dbe40a919dde740117b4638758fd937de5da