mod_proxy_http.c in mod_proxy_http in the Apache HTTP Server 2.2.9 through 2.2.15, 2.3.4-alpha, and 2.3.5-alpha on Windows, NetWare, and OS/2, in certain configurations involving proxy worker pools, does not properly detect timeouts, which allows remote attackers to obtain a potentially sensitive response intended for a different client in opportunistic circumstances via a normal HTTP request.