diff --git a/vendor/github.com/hashicorp/serf/coordinate/client.go b/vendor/github.com/hashicorp/serf/coordinate/client.go
index 63f6241411..403ec78014 100644
--- a/vendor/github.com/hashicorp/serf/coordinate/client.go
+++ b/vendor/github.com/hashicorp/serf/coordinate/client.go
@@ -205,6 +205,11 @@ func (c *Client) Update(node string, other *Coordinate, rtt time.Duration) (*Coo
 		return nil, err
 	}
 
+	const maxRTT = 10 * time.Second
+	if rtt <= 0 || rtt > maxRTT {
+		return nil, fmt.Errorf("round trip time not in valid range, duration %v is not a positive value less than %v ", rtt, maxRTT)
+	}
+
 	rttSeconds := c.latencyFilter(node, rtt.Seconds())
 	c.updateVivaldi(other, rttSeconds)
 	c.updateAdjustment(other, rttSeconds)
diff --git a/vendor/github.com/hashicorp/serf/serf/keymanager.go b/vendor/github.com/hashicorp/serf/serf/keymanager.go
index bea038cd24..fd53182fc5 100644
--- a/vendor/github.com/hashicorp/serf/serf/keymanager.go
+++ b/vendor/github.com/hashicorp/serf/serf/keymanager.go
@@ -189,4 +189,4 @@ func (k *KeyManager) ListKeysWithOptions(opts *KeyRequestOptions) (*KeyResponse,
 	defer k.l.RUnlock()
 
 	return k.handleKeyRequest("", listKeysQuery, opts)
-}
+}
\ No newline at end of file
diff --git a/vendor/github.com/hashicorp/serf/serf/serf.go b/vendor/github.com/hashicorp/serf/serf/serf.go
index 5940a67940..7256eafab1 100644
--- a/vendor/github.com/hashicorp/serf/serf/serf.go
+++ b/vendor/github.com/hashicorp/serf/serf/serf.go
@@ -1654,8 +1654,6 @@ func (s *Serf) Stats() map[string]string {
 	toString := func(v uint64) string {
 		return strconv.FormatUint(v, 10)
 	}
-	s.memberLock.RLock()
-	defer s.memberLock.RUnlock()
 	stats := map[string]string{
 		"members":      toString(uint64(len(s.members))),
 		"failed":       toString(uint64(len(s.failedMembers))),
diff --git a/vendor/vendor.json b/vendor/vendor.json
index b91c7913b6..fd9325169c 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -59,8 +59,8 @@
 		{"path":"github.com/hashicorp/net-rpc-msgpackrpc","checksumSHA1":"qnlqWJYV81ENr61SZk9c65R1mDo=","revision":"a14192a58a694c123d8fe5481d4a4727d6ae82f3","revisionTime":"2015-11-16T02:03:38Z"},
 		{"path":"github.com/hashicorp/raft","checksumSHA1":"JjJtGJi1ywWhVhs/PvTXxe4TeD8=","revision":"6d14f0c70869faabd9e60ba7ed88a6cbbd6a661f","revisionTime":"2017-10-03T22:09:13Z","version":"v1.0.0","versionExact":"v1.0.0"},
 		{"path":"github.com/hashicorp/raft-boltdb","checksumSHA1":"QAxukkv54/iIvLfsUP6IK4R0m/A=","revision":"d1e82c1ec3f15ee991f7cc7ffd5b67ff6f5bbaee","revisionTime":"2015-02-01T20:08:39Z"},
-		{"path":"github.com/hashicorp/serf/coordinate","checksumSHA1":"/oss17GO4hXGM7QnUdI3VzcAHzA=","comment":"v0.7.0-66-g6c4672d","revision":"c2e4be24cdc9031eb0ad869c5d160775efdf7d7a","revisionTime":"2017-05-25T23:15:04Z"},
-		{"path":"github.com/hashicorp/serf/serf","checksumSHA1":"3WPnGSL9ZK6EmkAE6tEW5SCxrd8=","comment":"v0.7.0-66-g6c4672d","revision":"b84a66cc5575994cb672940d244a2404141688c0","revisionTime":"2017-08-17T21:22:02Z"},
+		{"path":"github.com/hashicorp/serf/coordinate","checksumSHA1":"mS15CkImPzXYsgNwl3Mt9Gh3Vb0=","comment":"v0.7.0-66-g6c4672d","revision":"3615affef7125655e0dcf7c10fddbbde737fee35","revisionTime":"2017-10-20T15:11:25Z"},
+		{"path":"github.com/hashicorp/serf/serf","checksumSHA1":"3WPnGSL9ZK6EmkAE6tEW5SCxrd8=","comment":"v0.7.0-66-g6c4672d","revision":"3615affef7125655e0dcf7c10fddbbde737fee35","revisionTime":"2017-10-20T15:11:25Z"},
 		{"path":"github.com/hashicorp/yamux","checksumSHA1":"ZhK6IO2XN81Y+3RAjTcVm1Ic7oU=","revision":"d1caa6c97c9fc1cc9e83bbe34d0603f9ff0ce8bd","revisionTime":"2016-07-20T23:31:40Z"},
 		{"path":"github.com/mattn/go-isatty","checksumSHA1":"xZuhljnmBysJPta/lMyYmJdujCg=","revision":"66b8e73f3f5cda9f96b69efd03dd3d7fc4a5cdb8","revisionTime":"2016-08-06T12:27:52Z"},
 		{"path":"github.com/miekg/dns","checksumSHA1":"Jo+pItYOocIRdoFL0fc4nHhUEJY=","revision":"bbca4873b326f5dc54bfe31148446d4ed79a5a02","revisionTime":"2017-08-08T22:19:10Z"},