diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index 6ecb832a6..1f9e763d7 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -100,7 +100,7 @@ void CheckStl::iterators()
 
         // Scan through the rest of the code and see if the iterator is
         // used against other containers.
-        for (const Token *tok2 = var->nameToken(); tok2 != var->scope()->classEnd; tok2 = tok2->next()) {
+        for (const Token *tok2 = var->nameToken(); tok2 && tok2 != var->scope()->classEnd; tok2 = tok2->next()) {
             if (invalidationScope && tok2 == invalidationScope->classEnd)
                 validIterator = true; // Assume that the iterator becomes valid again
             if (containerAssignScope && tok2 == containerAssignScope->classEnd)
@@ -208,7 +208,7 @@ void CheckStl::iterators()
 
             // bailout handling. Assume that the iterator becomes valid if we see else.
             // TODO: better handling
-            else if (tok2->str() == "else") {
+            else if (tok2 && tok2->str() == "else") {
                 validIterator = true;
             }
         }
diff --git a/test/teststl.cpp b/test/teststl.cpp
index 22ec6bb18..3fd783371 100644
--- a/test/teststl.cpp
+++ b/test/teststl.cpp
@@ -45,6 +45,7 @@ private:
         TEST_CASE(iterator11);
         TEST_CASE(iterator12);
         TEST_CASE(iterator13);
+        TEST_CASE(iterator14); // #5598 invalid code causing a crash
 
         TEST_CASE(dereference);
         TEST_CASE(dereference_break);  // #3644 - handle "break"
@@ -440,6 +441,11 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void iterator14() {
+        check(" { { void foo() { struct }; template <typename> struct S { Used x; void bar() } auto f = [this] { }; } };");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     // Dereferencing invalid pointer
     void dereference() {
         check("void f()\n"