diff -Nru whoopsie-0.2.72/debian/changelog whoopsie-0.2.73~test1/debian/changelog
--- whoopsie-0.2.72/debian/changelog	2020-09-21 13:07:53.000000000 -0400
+++ whoopsie-0.2.73~test1/debian/changelog	2020-10-26 14:40:14.000000000 -0400
@@ -1,3 +1,12 @@
+whoopsie (0.2.73~test1) groovy; urgency=medium
+
+  * Attempt to fix double free issue (LP: #1899100)
+    - src/whoopsie.c: reject duplicate keys, re-order certain operations.
+    - src/tests/data/crash/invalid_key_duplicate,
+      src/tests/test_parse_report.c: added test for duplicate keys.
+
+ -- Marc Deslauriers <marc.deslauriers@ubuntu.com>  Mon, 26 Oct 2020 14:40:14 -0400
+
 whoopsie (0.2.72) groovy; urgency=medium
 
   * src/whoopsie.c: Do not upload AlsaInfo as it is redundant now that PaInfo
diff -Nru whoopsie-0.2.72/src/tests/data/crash/invalid_key_duplicate whoopsie-0.2.73~test1/src/tests/data/crash/invalid_key_duplicate
--- whoopsie-0.2.72/src/tests/data/crash/invalid_key_duplicate	1969-12-31 19:00:00.000000000 -0500
+++ whoopsie-0.2.73~test1/src/tests/data/crash/invalid_key_duplicate	2020-10-26 14:40:14.000000000 -0400
@@ -0,0 +1,13 @@
+ProblemType: Crash
+Architecture: amd64
+Architecture: i386
+Date: Thu Feb  2 17:09:31 2012
+ProcEnviron:
+ LANGUAGE=en_US:en
+ LC_CTYPE=en_US.UTF-8
+ LC_COLLATE=en_US.UTF-8
+ PATH=(custom, user)
+ LANG=en_US.UTF-8
+ LC_MESSAGES=en_US.UTF-8
+ SHELL=/bin/bash
+Uname: Linux 3.2.0-12-generic x86_64
diff -Nru whoopsie-0.2.72/src/tests/test_parse_report.c whoopsie-0.2.73~test1/src/tests/test_parse_report.c
--- whoopsie-0.2.72/src/tests/test_parse_report.c	2020-08-05 17:53:01.000000000 -0400
+++ whoopsie-0.2.73~test1/src/tests/test_parse_report.c	2020-10-26 14:40:14.000000000 -0400
@@ -449,6 +449,9 @@
     const char* empty_line_data[] = {
         TEST_DIR "/data/crash/invalid_value",
         "Report key must have a value." };
+    const char* duplicate_key_data[] = {
+        TEST_DIR "/data/crash/invalid_key_duplicate",
+        "Report key must not be a duplicate." };
 
     g_test_add_data_func ("/whoopsie/invalid_symlink",
                           symlink_data, test_report_expect_error);
@@ -466,6 +469,8 @@
                           no_spaces_data, test_report_expect_error);
     g_test_add_data_func ("/whoopsie/empty-line",
                           empty_line_data, test_report_expect_error);
+    g_test_add_data_func ("/whoopsie/duplicate_key",
+                          duplicate_key_data, test_report_expect_error);
 
     /* Run this last, so as to not mess with other tests. */
     g_test_add_func ("/whoopsie/drop-privileges", test_drop_privileges);
diff -Nru whoopsie-0.2.72/src/whoopsie.c whoopsie-0.2.73~test1/src/whoopsie.c
--- whoopsie-0.2.72/src/whoopsie.c	2020-09-21 13:06:16.000000000 -0400
+++ whoopsie-0.2.73~test1/src/whoopsie.c	2020-10-26 14:40:14.000000000 -0400
@@ -481,19 +481,19 @@
                                  0, "Report value too long.");
                     goto error;
                 }
+                g_hash_table_steal (hash_table, key);
                 value = g_realloc (value, value_pos + 1 + value_length + 1);
                 value_p = value + value_pos;
                 *value_p = '\n';
                 value_p++;
-                g_hash_table_steal (hash_table, key);
             } else {
-                value = g_realloc (value, value_length + 1);
-                value_p = value;
                 /* Make sure we properly free the old empty string value */
                 old_value = g_hash_table_lookup (hash_table, key);
                 if (old_value)
                     g_free (old_value);
                 g_hash_table_steal (hash_table, key);
+                value = g_realloc (value, value_length + 1);
+                value_p = value;
             }
             memcpy (value_p, p, value_length);
             value_p[value_length] = '\0';
@@ -502,6 +502,12 @@
                 if (*c != '\t' && *c >= '\0' && *c < ' ')
                     *c = '?';
             value_p += value_length;
+            if (g_hash_table_contains (hash_table, key) == TRUE) {
+                g_set_error (error,
+                    g_quark_from_static_string ("whoopsie-quark"),
+                    0, "Report key must not be a duplicate.");
+                goto error;
+            }
             g_hash_table_insert (hash_table, key, value ? value : g_strdup(""));
             p = token_p + 1;
         } else {
@@ -572,6 +578,12 @@
             }
             p = token_p + 1;
 
+            if (g_hash_table_contains (hash_table, key) == TRUE) {
+                g_set_error (error,
+                    g_quark_from_static_string ("whoopsie-quark"),
+                    0, "Report key must not be a duplicate.");
+                goto error;
+            }
             g_hash_table_insert (hash_table, key, value ? value : g_strdup(""));
         }
     }