diff --git a/contrib/epee/src/hex.cpp b/contrib/epee/src/hex.cpp
index 1c6d236dc..4a8f093e0 100644
--- a/contrib/epee/src/hex.cpp
+++ b/contrib/epee/src/hex.cpp
@@ -134,7 +134,7 @@ namespace epee
     // should we include a specific character
     auto include = [](char input) {
         // we ignore spaces and colons
-        return !std::isspace(input) && input != ':';
+        return !std::isspace(static_cast<unsigned char>(input)) && input != ':';
     };
 
     // the number of relevant characters to decode
@@ -153,7 +153,7 @@ namespace epee
 
     // convert a single hex character to an unsigned integer
     auto char_to_int = [](const char *input) {
-      switch (std::tolower(*input)) {
+      switch (std::tolower(static_cast<unsigned char>(*input))) {
         case '0': return  0;
         case '1': return  1;
         case '2': return  2;
@@ -184,6 +184,9 @@ namespace epee
 
       // convert two matching characters to int
       auto high = char_to_int(data++);
+      while (data != src.end() && !include(*data)) {
+        ++data;
+      }
       auto low  = char_to_int(data++);
 
       result.push_back(high << 4 | low);
diff --git a/tests/unit_tests/epee_utils.cpp b/tests/unit_tests/epee_utils.cpp
index 36a9ccdcc..6c9c52def 100644
--- a/tests/unit_tests/epee_utils.cpp
+++ b/tests/unit_tests/epee_utils.cpp
@@ -1221,6 +1221,9 @@ TEST(HexLocale, String)
     hex.assign("00:ff 0f:f0");
     EXPECT_EQ(source, epee::from_hex_locale::to_vector(hex));
 
+    hex.assign("0:0 f f 0:f f:0");
+    EXPECT_EQ(source, epee::from_hex_locale::to_vector(hex));
+
     hex.append("f0");
     EXPECT_EQ(source, epee::from_hex_locale::to_vector(boost::string_ref{hex.data(), hex.size() - 2}));
 }