Python 3.3.3 RC2 发布了，主要修复了一些安全性方面的问题，详细列表请看ChangeLog。
Issue #18603: Ensure that PyOS_mystricmp and PyOS_mystrnicmp are in the Python executable and not removed by the linker’s optimizer.
Issue #19279: UTF-7 decoder no more produces illegal strings.
Fix macro expansion of _PyErr_OCCURRED(), and make sure to use it in at least one place so as to avoid regressions.
Issue #19014: memoryview.cast() is now allowed on zero-length views.
Issue #19098: Prevent overflow in the compiler when the recursion limit is set absurdly high.
Issue #18942: sys._debugmallocstats() output was damaged on Windows.
Issue #18667: Add missing “HAVE_FCHOWNAT” symbol to posix._have_functions.
Issue #18368: PyOS_StdioReadline() no longer leaks memory when realloc() fails.
Issue #16741: Fix an error reporting in int().
Issue #17899: Fix rare file descriptor leak in os.listdir().
Issue #18552: Check return value of PyArena_AddPyObject() in obj2ast_object().
Issue #18560: Fix potential NULL pointer dereference in sum().
Issue #15905: Fix theoretical buffer overflow in handling of sys.argv, prefix and exec_prefix if the operation system does not obey MAXPATHLEN.
Issue #18344: Fix potential ref-leaks in _bufferedreader_read_all().
Issue #17872: Fix a segfault in marshal.load() when input stream returns more bytes than requested.
Issue #18426: Fix NULL pointer dereference in C extension import when PyModule_GetDef() returns an error.
Issue #18328: Reorder ops in PyThreadState_Delete*() functions. Now the tstate is first removed from TLS and then deallocated.
Issue #18184: PyUnicode_FromFormat() and PyUnicode_FromFormatV() now raise OverflowError when an argument of %c format is out of range.
Issue #18137: Detect integer overflow on precision in float.__format__() and complex.__format__().
Issue #18183: Fix various unicode operations on strings with large unicode codepoints.
Issue #18180: Fix ref leak in _PyImport_GetDynLoadWindows().
Issue #18038: SyntaxError raised during compilation sources with illegal encoding now always contains an encoding name.
Issue #17644: Fix a crash in str.format when curly braces are used in square brackets.
Issue #17983: Raise a SyntaxError for a global __class__ statement in a class body.
Issue #17927: Frame objects kept arguments alive if they had been copied into a cell, even if the cell was cleared.