diff --git a/dlls/winhttp/net.c b/dlls/winhttp/net.c
index 79e67890298..f362a8b554d 100644
--- a/dlls/winhttp/net.c
+++ b/dlls/winhttp/net.c
@@ -566,7 +566,7 @@ DWORD netconn_set_timeout( netconn_t *netconn, BOOL send, int value )
     return ERROR_SUCCESS;
 }
 
-BOOL netconn_resolve( WCHAR *hostnameW, INTERNET_PORT port, struct sockaddr_in *sa )
+BOOL netconn_resolve( WCHAR *hostnameW, INTERNET_PORT port, struct sockaddr *sa, socklen_t *sa_len )
 {
     char *hostname;
 #ifdef HAVE_GETADDRINFO
@@ -574,6 +574,7 @@ BOOL netconn_resolve( WCHAR *hostnameW, INTERNET_PORT port, struct sockaddr_in *
     int ret;
 #else
     struct hostent *he;
+    struct sockaddr_in *sin = (struct sockaddr_in *)sa;
 #endif
 
     if (!(hostname = strdupWA( hostnameW ))) return FALSE;
@@ -589,10 +590,17 @@ BOOL netconn_resolve( WCHAR *hostnameW, INTERNET_PORT port, struct sockaddr_in *
         TRACE("failed to get address of %s (%s)\n", debugstr_w(hostnameW), gai_strerror(ret));
         return FALSE;
     }
+    if (*sa_len < sizeof(struct sockaddr_in))
+    {
+        WARN("address too small\n");
+        freeaddrinfo( res );
+        return FALSE;
+    }
+    *sa_len = sizeof(struct sockaddr_in);
     memset( sa, 0, sizeof(struct sockaddr_in) );
-    memcpy( &sa->sin_addr, &((struct sockaddr_in *)res->ai_addr)->sin_addr, sizeof(struct in_addr) );
-    sa->sin_family = res->ai_family;
-    sa->sin_port = htons( port );
+    memcpy( &((struct sockaddr_in *)sa)->sin_addr, &((struct sockaddr_in *)res->ai_addr)->sin_addr, sizeof(struct in_addr) );
+    ((struct sockaddr_in *)sa)->sin_family = res->ai_family;
+    ((struct sockaddr_in *)sa)->sin_port = htons( port );
 
     freeaddrinfo( res );
 #else
@@ -606,10 +614,17 @@ BOOL netconn_resolve( WCHAR *hostnameW, INTERNET_PORT port, struct sockaddr_in *
         LeaveCriticalSection( &cs_gethostbyname );
         return FALSE;
     }
+    if (*sa_len < sizeof(struct sockaddr_in))
+    {
+        WARN("address too small\n");
+        LeaveCriticalSection( &cs_gethostbyname );
+        return FALSE;
+    }
+    *sa_len = sizeof(struct sockaddr_in);
     memset( sa, 0, sizeof(struct sockaddr_in) );
-    memcpy( &sa->sin_addr, he->h_addr, he->h_length );
-    sa->sin_family = he->h_addrtype;
-    sa->sin_port = htons( port );
+    memcpy( &sin->sin_addr, he->h_addr, he->h_length );
+    sin->sin_family = he->h_addrtype;
+    sin->sin_port = htons( port );
 
     LeaveCriticalSection( &cs_gethostbyname );
 #endif
diff --git a/dlls/winhttp/request.c b/dlls/winhttp/request.c
index ddfac13c449..f088c40855c 100644
--- a/dlls/winhttp/request.c
+++ b/dlls/winhttp/request.c
@@ -716,6 +716,7 @@ static BOOL open_connection( request_t *request )
     char address[32];
     WCHAR *addressW;
     INTERNET_PORT port;
+    socklen_t slen;
 
     if (netconn_connected( &request->netconn )) return TRUE;
 
@@ -724,7 +725,8 @@ static BOOL open_connection( request_t *request )
 
     send_callback( &request->hdr, WINHTTP_CALLBACK_STATUS_RESOLVING_NAME, connect->servername, strlenW(connect->servername) + 1 );
 
-    if (!netconn_resolve( connect->servername, port, &connect->sockaddr )) return FALSE;
+    slen = sizeof(connect->sockaddr);
+    if (!netconn_resolve( connect->servername, port, (struct sockaddr *)&connect->sockaddr, &slen )) return FALSE;
     inet_ntop( connect->sockaddr.sin_family, &connect->sockaddr.sin_addr, address, sizeof(address) );
     addressW = strdupAW( address );
 
diff --git a/dlls/winhttp/winhttp_private.h b/dlls/winhttp/winhttp_private.h
index 823d0ae2047..750acf50aed 100644
--- a/dlls/winhttp/winhttp_private.h
+++ b/dlls/winhttp/winhttp_private.h
@@ -211,7 +211,7 @@ BOOL netconn_get_next_line( netconn_t *, char *, DWORD * );
 BOOL netconn_init( netconn_t *, BOOL );
 BOOL netconn_query_data_available( netconn_t *, DWORD * );
 BOOL netconn_recv( netconn_t *, void *, size_t, int, int * );
-BOOL netconn_resolve( WCHAR *, INTERNET_PORT, struct sockaddr_in * );
+BOOL netconn_resolve( WCHAR *, INTERNET_PORT, struct sockaddr *, socklen_t * );
 BOOL netconn_secure_connect( netconn_t * );
 BOOL netconn_send( netconn_t *, const void *, size_t, int, int * );
 DWORD netconn_set_timeout( netconn_t *, BOOL, int );