diff --git a/src/sudo.c b/src/sudo.c
index 0ed053839..89d97b6e8 100644
--- a/src/sudo.c
+++ b/src/sudo.c
@@ -341,13 +341,48 @@ access_denied:
     return EXIT_FAILURE;
 }
 
+/*
+ * Set the time zone using tzset(3), removing the user's TZ
+ * environment variable.  The original value of TZ may still
+ * be present in the command's environment, depending on sudoers.
+ */
+static void
+set_time_zone(void)
+{
+    /* Use system time zone, not user-specified. */
+    unsetenv("TZ");
+    (void) tzset();
+}
+
 int
 os_init_common(int argc, char *argv[], char *envp[])
 {
+    extern char **environ;
+    int envc;
 #ifdef STATIC_SUDOERS_PLUGIN
     preload_static_symbols();
 #endif
     gc_init();
+
+    /*
+     * Make a copy of environ[] that is distinct from envp[].
+     * This allows us to remove variables from sudo's environment
+     * while still providing the original envp to the plugins.
+     */
+    for (envc = 0; envp[envc] != NULL; envc++)
+	continue;
+    if (envc != 0) {
+	char **new_env = reallocarray(NULL, sizeof(char *), envc + 1);
+	if (new_env == NULL || !gc_add(GC_PTR, new_env)) {
+	    sudo_fatalx_nodebug(U_("%s: %s"), __func__,
+		U_("unable to allocate memory"));
+	}
+	for (envc = 0; envp[envc] != NULL; envc++)
+	    new_env[envc] = envp[envc];
+	new_env[envc] = NULL;
+	environ = new_env;
+    }
+
     return 0;
 }