This morning came news of a remote exploitable vulnerability in Apache mod_rewrite, the exploit is pretty difficult and requires weird setups on your side, but you should be upgrading all your kit.
More info at Secunia
A vulnerability has been reported in Apache HTTP Server, which potentially can be exploited by malicious people to compromise a vulnerable system.
The vulnerability is caused by a off-by-one error in mod_rewrite and can be exploited to cause a one-byte buffer overflow.
Successful exploitation may crash the web server process or allow execution of arbitrary code.
