diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index d2805f52e1e..3d880fdb46d 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -3619,6 +3619,14 @@ bool qEnvironmentVariableIsSet(const char *varName) noexcept
 */
 bool qputenv(const char *varName, const QByteArray &value)
 {
+    // protect against non-NUL-terminated QByteArrays:
+    if (!const_cast<QByteArray&>(value).data_ptr()->isMutable()) {
+        QByteArray copy(value);
+        copy.reserve(copy.size() + 1); // ensures NUL termination (and isMutable() even for size==0
+                                       // (unlike detach()) to avoid infinite recursion)
+        return qputenv(varName, copy);
+    }
+
 #if defined(Q_CC_MSVC)
     const auto locker = qt_scoped_lock(environmentMutex);
     return _putenv_s(varName, value.constData()) == 0;
diff --git a/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp b/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
index 77a7fa41942..f914ee5f232 100644
--- a/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
+++ b/tests/auto/corelib/global/qgetputenv/tst_qgetputenv.cpp
@@ -60,7 +60,11 @@ void tst_QGetPutEnv::getSetCheck()
     QCOMPARE(sresult, QString());
 #endif
 
-    QVERIFY(qputenv(varName, QByteArray("supervalue")));
+    constexpr char varValueFullString[] = "supervalue123";
+    const auto varValueQBA = QByteArray::fromRawData(varValueFullString, sizeof varValueFullString - 4);
+    QCOMPARE_EQ(varValueQBA, "supervalue");
+
+    QVERIFY(qputenv(varName, varValueQBA));
 
     QVERIFY(qEnvironmentVariableIsSet(varName));
     QVERIFY(!qEnvironmentVariableIsEmpty(varName));