diff --git a/src/corelib/text/qbytearrayalgorithms.h b/src/corelib/text/qbytearrayalgorithms.h
index 649ec2e39bd..5b2b71838fa 100644
--- a/src/corelib/text/qbytearrayalgorithms.h
+++ b/src/corelib/text/qbytearrayalgorithms.h
@@ -139,8 +139,10 @@ Q_CORE_EXPORT int qstrnicmp(const char *, const char *, size_t len);
 Q_CORE_EXPORT int qstrnicmp(const char *, qsizetype, const char *, qsizetype = -1);
 
 // implemented in qvsnprintf.cpp
-Q_CORE_EXPORT int qvsnprintf(char *str, size_t n, const char *fmt, va_list ap);
-Q_CORE_EXPORT int qsnprintf(char *str, size_t n, const char *fmt, ...);
+Q_CORE_EXPORT int qvsnprintf(char *str, size_t n, const char *fmt, va_list ap)
+    Q_ATTRIBUTE_FORMAT_PRINTF(3, 0);
+Q_CORE_EXPORT int qsnprintf(char *str, size_t n, const char *fmt, ...)
+    Q_ATTRIBUTE_FORMAT_PRINTF(3, 4);
 
 // qChecksum: Internet checksum
 Q_CORE_EXPORT quint16 qChecksum(QByteArrayView data, Qt::ChecksumType standard = Qt::ChecksumIso3309);
diff --git a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
index fea603faed7..29103b5e3d4 100644
--- a/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
+++ b/tests/auto/corelib/text/qbytearray/tst_qbytearray.cpp
@@ -716,7 +716,11 @@ void tst_QByteArray::qvsnprintf()
 
 #ifndef Q_OS_WIN
     memset(buf, 42, sizeof(buf));
+    QT_WARNING_PUSH
+    QT_WARNING_DISABLE_GCC("-Wformat-zero-length")
+    QT_WARNING_DISABLE_CLANG("-Wformat-zero-length")
     QCOMPARE(::qsnprintf(buf, 10, ""), 0);
+    QT_WARNING_POP
 #endif
 }