diff --git a/main.cpp b/main.cpp
index 3f02773..8173e99 100644
--- a/main.cpp
+++ b/main.cpp
@@ -121,6 +121,10 @@ int main(int argc, char **argv)
             std::cout << "error: could not open file '" << filename << "'" << std::endl;
             std::exit(1);
         }
+        if (!simplecpp::isFile(filename)) {
+            std::cout << "error: could not open file '" << filename << "' - not a regular file" << std::endl;
+            std::exit(1);
+        }
         rawtokens = new simplecpp::TokenList(f, files,filename,&outputList);
     }
     else {
diff --git a/simplecpp.cpp b/simplecpp.cpp
index 9c3f3a0..66859d3 100755
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -30,6 +30,7 @@
 #include <stack>
 #include <stdexcept>
 #include <string>
+#include <sys/stat.h>
 #if __cplusplus >= 201103L
 #ifdef SIMPLECPP_WINDOWS
 #include <mutex>
@@ -39,6 +40,12 @@
 #include <utility>
 #include <vector>
 
+#ifdef _WIN32
+using mode_t = unsigned short;
+#else
+#include <sys/types.h>
+#endif
+
 #ifdef SIMPLECPP_WINDOWS
 #include <windows.h>
 #undef ERROR
@@ -3077,9 +3084,11 @@ static std::string openHeader(std::ifstream &f, const std::string &path)
     if (nonExistingFilesCache.contains(simplePath))
         return "";  // file is known not to exist, skip expensive file open call
 #endif
-    f.open(simplePath.c_str());
-    if (f.is_open())
-        return simplePath;
+    if (simplecpp::isFile(simplePath)) {
+        f.open(simplePath.c_str());
+        if (f.is_open())
+            return simplePath;
+    }
 #ifdef SIMPLECPP_WINDOWS
     nonExistingFilesCache.add(simplePath);
 #endif
@@ -3184,18 +3193,19 @@ std::map<std::string, simplecpp::TokenList*> simplecpp::load(const simplecpp::To
         if (ret.find(filename) != ret.end())
             continue;
 
-        std::ifstream fin(filename.c_str());
-        if (!fin.is_open()) {
-            if (outputList) {
-                simplecpp::Output err(filenames);
-                err.type = simplecpp::Output::EXPLICIT_INCLUDE_NOT_FOUND;
-                err.location = Location(filenames);
-                err.msg = "Can not open include file '" + filename + "' that is explicitly included.";
-                outputList->push_back(err);
+        {
+            std::ifstream fin(filename.c_str());
+            if (!fin.is_open() || !isFile(filename)) {
+                if (outputList) {
+                    simplecpp::Output err(filenames);
+                    err.type = simplecpp::Output::EXPLICIT_INCLUDE_NOT_FOUND;
+                    err.location = Location(filenames);
+                    err.msg = "Can not open include file '" + filename + "' that is explicitly included.";
+                    outputList->push_back(err);
+                }
+                continue;
             }
-            continue;
         }
-        fin.close();
 
         TokenList *tokenlist = new TokenList(filename, filenames, outputList);
         if (!tokenlist->front()) {
@@ -3835,6 +3845,24 @@ std::string simplecpp::getCppStdString(const std::string &std)
     return "";
 }
 
+static mode_t file_type(const std::string &path)
+{
+    struct stat file_stat;
+    if (stat(path.c_str(), &file_stat) == -1)
+        return 0;
+    return file_stat.st_mode & S_IFMT;
+}
+
+bool simplecpp::isFile(const std::string &path)
+{
+    return file_type(path) == S_IFREG;
+}
+
+bool simplecpp::isDirectory(const std::string &path)
+{
+    return file_type(path) == S_IFDIR;
+}
+
 #if (__cplusplus < 201103L) && !defined(__APPLE__)
 #undef nullptr
 #endif
diff --git a/simplecpp.h b/simplecpp.h
index 398024d..c2938be 100755
--- a/simplecpp.h
+++ b/simplecpp.h
@@ -373,6 +373,20 @@ namespace simplecpp {
 
     /** Returns the __cplusplus value for a given standard */
     SIMPLECPP_LIB std::string getCppStdString(const std::string &std);
+
+    /**
+     * @brief Checks if given path is a file
+     * @param path Path to be checked
+     * @return true if given path is a file
+     */
+    SIMPLECPP_LIB bool isFile(const std::string &path);
+
+    /**
+     * @brief Checks if a given path is a directory
+     * @param path Path to be checked
+     * @return true if given path is a directory
+     */
+    SIMPLECPP_LIB bool isDirectory(const std::string &path);
 }
 
 #if defined(_MSC_VER)
diff --git a/test.cpp b/test.cpp
index d00658a..2c835be 100644
--- a/test.cpp
+++ b/test.cpp
@@ -1779,6 +1779,44 @@ static void missingHeader3()
     ASSERT_EQUALS("", toString(outputList));
 }
 
+#ifndef _WIN32
+static void missingHeader4()
+{
+    // this is a directory
+    const char code[] = "#include \"/\"\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("", preprocess(code, &outputList));
+    ASSERT_EQUALS("file0,1,missing_header,Header not found: \"/\"\n", toString(outputList));
+}
+
+static void missingHeader5()
+{
+    // this is a directory
+    const char code[] = "#include \"/usr\"\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("", preprocess(code, &outputList));
+    ASSERT_EQUALS("file0,1,missing_header,Header not found: \"/usr\"\n", toString(outputList));
+}
+
+static void missingHeader6()
+{
+    // this is a directory
+    const char code[] = "#include </>\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("", preprocess(code, &outputList));
+    ASSERT_EQUALS("file0,1,missing_header,Header not found: </>\n", toString(outputList));
+}
+
+static void missingHeader7()
+{
+    // this is a directory
+    const char code[] = "#include </usr>\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("", preprocess(code, &outputList));
+    ASSERT_EQUALS("file0,1,missing_header,Header not found: </usr>\n", toString(outputList));
+}
+#endif
+
 static void nestedInclude()
 {
     const char code[] = "#include \"test.h\"\n";
@@ -2806,6 +2844,16 @@ static void fuzz_crash()
     }
 }
 
+static void leak()
+{
+    const char code[] = "#include</\\\\>\n"
+                        "#include</\\\\>\n";
+    simplecpp::OutputList outputList;
+    ASSERT_EQUALS("", preprocess(code, &outputList));
+    ASSERT_EQUALS("file0,1,missing_header,Header not found: </\\\\>\n"
+                  "file0,2,missing_header,Header not found: </\\\\>\n", toString(outputList));
+}
+
 int main(int argc, char **argv)
 {
     TEST_CASE(backslash);
@@ -2959,6 +3007,12 @@ int main(int argc, char **argv)
     TEST_CASE(missingHeader1);
     TEST_CASE(missingHeader2);
     TEST_CASE(missingHeader3);
+#ifndef _WIN32
+    TEST_CASE(missingHeader4);
+    TEST_CASE(missingHeader5);
+    TEST_CASE(missingHeader6);
+    TEST_CASE(missingHeader7);
+#endif
     TEST_CASE(nestedInclude);
     TEST_CASE(systemInclude);
 
@@ -3037,5 +3091,7 @@ int main(int argc, char **argv)
 
     TEST_CASE(fuzz_crash);
 
+    TEST_CASE(leak);
+
     return numberOfFailedAssertions > 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }