diff -r -U3 plasma-workspace-5.18.4.1.orig/startkde/startplasma.cpp plasma-workspace-5.18.4.1/startkde/startplasma.cpp
--- plasma-workspace-5.18.4.1.orig/startkde/startplasma.cpp	2020-03-31 17:33:37.000000000 +0300
+++ plasma-workspace-5.18.4.1/startkde/startplasma.cpp	2020-04-03 20:43:32.178541309 +0300
@@ -28,6 +28,9 @@
 #include <QDBusConnectionInterface>
 #include <QDBusServiceWatcher>

+#include <QRegularExpression>
+#include <QProcessEnvironment>
+
 #include <KConfig>
 #include <KConfigGroup>
 
@@ -64,8 +66,26 @@
 int runSync(const QString& program, const QStringList &args, const QStringList &env)
 {
     QProcess p;
-    if (!env.isEmpty())
-        p.setEnvironment(QProcess::systemEnvironment() << env);
+    auto pEnv = QProcessEnvironment::systemEnvironment();
+    if (!env.isEmpty()) {
+        for (const auto &value : env) {
+            int pos = value.indexOf(QStringLiteral("="));
+            if (pos != -1) {
+                pEnv.insert(value.left(pos), value.mid(pos+1));
+            }
+        }
+    }
+    if (program.endsWith(QStringLiteral("dbus-update-activation-environment"))) {
+        const QRegularExpression re(QStringLiteral("[^A-Z0-9_]"));
+        for (const auto &key : pEnv.keys()) {
+            const auto match = re.match(key);
+            if (match.hasMatch()) {
+                pEnv.remove(key);
+                qInfo() << "program:" << program << "environment variable removed:" << key;
+            }
+        }
+    }
+    p.setProcessEnvironment(pEnv);
     p.setProcessChannelMode(QProcess::ForwardedChannels);
     p.start(program, args);
 //     qDebug() << "started..." << program << args;