diff --git a/doxgen-1.9.1-crash-when-parsing-config-file-part2.patch b/doxgen-1.9.1-crash-when-parsing-config-file-part2.patch
new file mode 100644
index 0000000..38465ff
--- /dev/null
+++ b/doxgen-1.9.1-crash-when-parsing-config-file-part2.patch
@@ -0,0 +1,22 @@
+diff -up doxygen/src/configimpl.l.orig doxygen/src/configimpl.l
+--- doxygen/src/configimpl.l.orig	2021-01-19 17:25:00.933789247 +0100
++++ doxygen/src/configimpl.l	2021-01-19 17:26:09.704744240 +0100
+@@ -1175,8 +1175,7 @@ static void substEnvVarsInStrList(String
+   for (const auto &s : sl)
+   {
+     QCString result = s.c_str();
+-    // an argument with quotes will have an extra space at the end, so wasQuoted will be TRUE.
+-    bool wasQuoted = (result.find(' ')!=-1) || (result.find('\t')!=-1);
++    bool wasQuoted = (result.find(' ')!=-1) || (result.find('\t')!=-1) || (result.find('"')!=-1);
+     // here we strip the quote again
+     substEnvVarsInString(result);
+ 
+@@ -1229,7 +1228,7 @@ static void substEnvVarsInStrList(String
+       }
+       if (p!=l) // add the leftover as a string
+       {
+-        results.push_back(result.right(l-p).data());
++        results.push_back(result.right(l-p).str());
+       }
+     }
+     else // just goto the next element in the list