diff --git a/app-misc/vlock/files/vlock-2.2.3-echo-printf.patch b/app-misc/vlock/files/vlock-2.2.3-echo-printf.patch
new file mode 100644
index 0000000000000..fd3653fb28242
--- /dev/null
+++ b/app-misc/vlock/files/vlock-2.2.3-echo-printf.patch
@@ -0,0 +1,11 @@
+--- a/vlock       2020-06-22 10:03:48.700469805 -0000
++++ b/vlock       2020-06-22 10:03:57.880385148 -0000
+@@ -17,7 +17,7 @@
+ set -e
+ 
+ # Magic characters to clear the terminal.
+-CLEAR_SCREEN="`echo -e '\033[H\033[J'`"
++CLEAR_SCREEN="`printf '\033[H\033[J'`"
+ 
+ # Enter message that is common to different the messages.
+ VLOCK_ENTER_PROMPT="Please press [ENTER] to unlock."
diff --git a/app-misc/vlock/vlock-2.2.3-r1.ebuild b/app-misc/vlock/vlock-2.2.3-r1.ebuild
index b6c8a2c4b177a..6bac4b08b79ec 100644
--- a/app-misc/vlock/vlock-2.2.3-r1.ebuild
+++ b/app-misc/vlock/vlock-2.2.3-r1.ebuild
@@ -54,5 +54,9 @@ src_configure() {
 
 src_install() {
 	default
+
+	# See bug #637598.
+	epatch "${FILESDIR}/${P}-echo-printf.patch"
+
 	use pam && pamd_mimic_system vlock auth
 }