FreeBSD Security Advisory FreeBSD-SA-04:03.jail - A vulnerability has been found where jailed processes can attach to other jails. A programming error has been found in the jail_attach(2) system call which affects the way that system call verifies the privilege level of the calling process. Instead of failing immediately if the calling process was already jailed, the jail_attach(2) system call would fail only after changing the calling process's root directory.
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