diff --git a/nvm.sh b/nvm.sh
index 9319521..b2af93c 100644
--- a/nvm.sh
+++ b/nvm.sh
@@ -2023,14 +2023,25 @@ nvm_is_merged_node_version() {
 }
 
 nvm_get_mirror() {
+  local NVM_MIRROR
+  NVM_MIRROR=''
   case "${1}-${2}" in
-    node-std) nvm_echo "${NVM_NODEJS_ORG_MIRROR:-https://nodejs.org/dist}" ;;
-    iojs-std) nvm_echo "${NVM_IOJS_ORG_MIRROR:-https://iojs.org/dist}" ;;
+    node-std) NVM_MIRROR="${NVM_NODEJS_ORG_MIRROR:-https://nodejs.org/dist}" ;;
+    iojs-std) NVM_MIRROR="${NVM_IOJS_ORG_MIRROR:-https://iojs.org/dist}" ;;
     *)
       nvm_err 'unknown type of node.js or io.js release'
       return 1
     ;;
   esac
+
+  case "${NVM_MIRROR}" in
+    *\`* | *\\* | *\'* | *\(* )
+      nvm_err '$NVM_NODEJS_ORG_MIRROR and $NVM_IOJS_ORG_MIRROR may only contain a URL'
+      return 2
+    ;;
+  esac
+
+  nvm_echo "${NVM_MIRROR}"
 }
 
 # args: os, prefixed version, version, tarball, extract directory
diff --git a/test/fast/Unit tests/nvm_get_mirror b/test/fast/Unit tests/nvm_get_mirror
index 8d4b192..1980f38 100755
--- a/test/fast/Unit tests/nvm_get_mirror	
+++ b/test/fast/Unit tests/nvm_get_mirror	
@@ -30,3 +30,11 @@ unset NVM_NODEJS_ORG_MIRROR
 NVM_IOJS_ORG_MIRROR="test://domain"
 [ "$(nvm_get_mirror iojs std)" = "test://domain" ] || die "iojs-std mirror should respect NVM_IOJS_ORG_MIRROR"
 unset NVM_IOJS_ORG_MIRROR
+
+NVM_NODEJS_ORG_MIRROR='`do something bad`'
+! nvm_get_mirror node std || die 'NVM_NODEJS_ORG_MIRROR errors with command injection attempt'
+[ "$(nvm_get_mirror node std)" = "" ] || die 'NVM_NODEJS_ORG_MIRROR is protected against command injection'
+
+NVM_IOJS_ORG_MIRROR='`do something bad`'
+! nvm_get_mirror iojs std || die 'NVM_IOJS_ORG_MIRROR errors with command injection attempt'
+[ "$(nvm_get_mirror iojs std)" = "" ] || die 'NVM_IOJS_ORG_MIRROR is protected against command injection'