diff --git a/go.mod b/go.mod
index bb39d2e19..2d4487426 100644
--- a/go.mod
+++ b/go.mod
@@ -56,7 +56,7 @@ require (
 	github.com/hashicorp/go-immutable-radix v0.0.0-20180129170900-7f3cd4390caa // indirect
 	github.com/hashicorp/go-msgpack v0.0.0-20150518234257-fa3f63826f7c // indirect
 	github.com/hashicorp/go-multierror v1.0.0
-	github.com/hashicorp/go-plugin v0.0.0-20190212232519-b838ffee39ce
+	github.com/hashicorp/go-plugin v0.0.0-20190220160451-3f118e8ee104
 	github.com/hashicorp/go-retryablehttp v0.5.1
 	github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90
 	github.com/hashicorp/go-sockaddr v0.0.0-20180320115054-6d291a969b86 // indirect
diff --git a/go.sum b/go.sum
index 98a102078..fb9eed33c 100644
--- a/go.sum
+++ b/go.sum
@@ -150,6 +150,8 @@ github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHh
 github.com/hashicorp/go-plugin v0.0.0-20170816151819-a5174f84d7f8/go.mod h1:JSqWYsict+jzcj0+xElxyrBQRPNoiWQuddnxArJ7XHQ=
 github.com/hashicorp/go-plugin v0.0.0-20190212232519-b838ffee39ce h1:I3KJUf8jyMubLFeHit2ibr9YeVxJX2CXMXVM6xlB+Qk=
 github.com/hashicorp/go-plugin v0.0.0-20190212232519-b838ffee39ce/go.mod h1:++UyYGoz3o5w9ZzAdZxtQKrWWP+iqPBn3cQptSMzBuY=
+github.com/hashicorp/go-plugin v0.0.0-20190220160451-3f118e8ee104 h1:9iQ/zrTOJqzP+kH37s6xNb6T1RysiT7fnDD3DJbspVw=
+github.com/hashicorp/go-plugin v0.0.0-20190220160451-3f118e8ee104/go.mod h1:++UyYGoz3o5w9ZzAdZxtQKrWWP+iqPBn3cQptSMzBuY=
 github.com/hashicorp/go-retryablehttp v0.5.1 h1:Vsx5XKPqPs3M6sM4U4GWyUqFS8aBiL9U5gkgvpkg4SE=
 github.com/hashicorp/go-retryablehttp v0.5.1/go.mod h1:9B5zBasrRhHXnJnui7y6sL7es7NDiJgTc6Er0maI1Xs=
 github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90 h1:VBj0QYQ0u2MCJzBfeYXGexnAl17GsH1yidnoxCqqD9E=
diff --git a/vendor/github.com/hashicorp/go-plugin/client.go b/vendor/github.com/hashicorp/go-plugin/client.go
index 42de0fc50..2a8b42fc3 100644
--- a/vendor/github.com/hashicorp/go-plugin/client.go
+++ b/vendor/github.com/hashicorp/go-plugin/client.go
@@ -21,7 +21,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
-	"unicode"
 
 	hclog "github.com/hashicorp/go-hclog"
 )
@@ -933,21 +932,48 @@ func (c *Client) dialer(_ string, timeout time.Duration) (net.Conn, error) {
 	return conn, nil
 }
 
+var stdErrBufferSize = 64 * 1024
+
 func (c *Client) logStderr(r io.Reader) {
 	defer c.clientWaitGroup.Done()
-
-	scanner := bufio.NewScanner(r)
 	l := c.logger.Named(filepath.Base(c.config.Cmd.Path))
 
-	for scanner.Scan() {
-		line := scanner.Text()
-		c.config.Stderr.Write([]byte(line + "\n"))
-		line = strings.TrimRightFunc(line, unicode.IsSpace)
+	reader := bufio.NewReaderSize(r, stdErrBufferSize)
+	// continuation indicates the previous line was a prefix
+	continuation := false
+
+	for {
+		line, isPrefix, err := reader.ReadLine()
+		switch {
+		case err == io.EOF:
+			return
+		case err != nil:
+			l.Error("reading plugin stderr", "error", err)
+			return
+		}
+
+		c.config.Stderr.Write(line)
+
+		// The line was longer than our max token size, so it's likely
+		// incomplete and won't unmarshal.
+		if isPrefix || continuation {
+			l.Debug(string(line))
+
+			// if we're finishing a continued line, add the newline back in
+			if !isPrefix {
+				c.config.Stderr.Write([]byte{'\n'})
+			}
+
+			continuation = isPrefix
+			continue
+		}
+
+		c.config.Stderr.Write([]byte{'\n'})
 
 		entry, err := parseJSON(line)
 		// If output is not JSON format, print directly to Debug
 		if err != nil {
-			l.Debug(line)
+			l.Debug(string(line))
 		} else {
 			out := flattenKVPairs(entry.KVPairs)
 
@@ -966,8 +992,4 @@ func (c *Client) logStderr(r io.Reader) {
 			}
 		}
 	}
-
-	if err := scanner.Err(); err != nil {
-		l.Error("reading plugin stderr", "error", err)
-	}
 }
diff --git a/vendor/github.com/hashicorp/go-plugin/log_entry.go b/vendor/github.com/hashicorp/go-plugin/log_entry.go
index 2996c14c3..fb2ef930c 100644
--- a/vendor/github.com/hashicorp/go-plugin/log_entry.go
+++ b/vendor/github.com/hashicorp/go-plugin/log_entry.go
@@ -32,11 +32,11 @@ func flattenKVPairs(kvs []*logEntryKV) []interface{} {
 }
 
 // parseJSON handles parsing JSON output
-func parseJSON(input string) (*logEntry, error) {
+func parseJSON(input []byte) (*logEntry, error) {
 	var raw map[string]interface{}
 	entry := &logEntry{}
 
-	err := json.Unmarshal([]byte(input), &raw)
+	err := json.Unmarshal(input, &raw)
 	if err != nil {
 		return nil, err
 	}
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 6ed05f1e5..fa7116ee1 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -389,7 +389,7 @@ github.com/hashicorp/go-getter/helper/url
 github.com/hashicorp/go-hclog
 # github.com/hashicorp/go-multierror v1.0.0
 github.com/hashicorp/go-multierror
-# github.com/hashicorp/go-plugin v0.0.0-20190212232519-b838ffee39ce
+# github.com/hashicorp/go-plugin v0.0.0-20190220160451-3f118e8ee104
 github.com/hashicorp/go-plugin
 github.com/hashicorp/go-plugin/internal/plugin
 # github.com/hashicorp/go-retryablehttp v0.5.1