diff --git a/channels/rdpecam/common/rdpecam-utils.h b/channels/rdpecam/common/rdpecam-utils.h
index 080cb0527..b1d27c798 100644
--- a/channels/rdpecam/common/rdpecam-utils.h
+++ b/channels/rdpecam/common/rdpecam-utils.h
@@ -32,7 +32,7 @@ static inline void rdpecam_PrintWarning(wLog* log, const char* file, const char*
                                         WINPR_FORMAT_ARG const char* fmt, ...)
 {
 	const DWORD level = WLOG_WARN;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, fmt);
 	if (WLog_IsLevelActive(log, level))
diff --git a/channels/rdpei/client/rdpei_main.c b/channels/rdpei/client/rdpei_main.c
index fc5477b87..43e4e4796 100644
--- a/channels/rdpei/client/rdpei_main.c
+++ b/channels/rdpei/client/rdpei_main.c
@@ -1202,7 +1202,7 @@ static UINT rdpei_touch_raw_event(RdpeiClientContext* context, INT32 externalId,
                                   INT32* contactId, UINT32 flags, UINT32 fieldFlags, ...)
 {
 	UINT rc = 0;
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, fieldFlags);
 	rc = rdpei_touch_process(context, externalId, flags, x, y, contactId, fieldFlags, ap);
 	va_end(ap);
@@ -1345,7 +1345,7 @@ static UINT rdpei_pen_begin(RdpeiClientContext* context, INT32 externalId, UINT3
                             INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
@@ -1366,7 +1366,7 @@ static UINT rdpei_pen_update(RdpeiClientContext* context, INT32 externalId, UINT
                              INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
@@ -1386,7 +1386,7 @@ static UINT rdpei_pen_end(RdpeiClientContext* context, INT32 externalId, UINT32
                           INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
 	                          RDPINPUT_CONTACT_FLAG_UP | RDPINPUT_CONTACT_FLAG_INRANGE, fieldFlags,
@@ -1404,7 +1404,7 @@ static UINT rdpei_pen_hover_begin(RdpeiClientContext* context, INT32 externalId,
                                   INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
@@ -1424,7 +1424,7 @@ static UINT rdpei_pen_hover_update(RdpeiClientContext* context, INT32 externalId
                                    INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
@@ -1444,7 +1444,7 @@ static UINT rdpei_pen_hover_cancel(RdpeiClientContext* context, INT32 externalId
                                    INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId,
@@ -1459,7 +1459,7 @@ static UINT rdpei_pen_raw_event(RdpeiClientContext* context, INT32 externalId, U
                                 UINT32 fieldFlags, INT32 x, INT32 y, ...)
 {
 	UINT error = 0;
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, y);
 	error = rdpei_pen_process(context, externalId, contactFlags, fieldFlags, x, y, ap);
diff --git a/client/Android/Studio/freeRDPCore/src/main/cpp/android_jni_callback.c b/client/Android/Studio/freeRDPCore/src/main/cpp/android_jni_callback.c
index b6ebe751a..a4e8214bd 100644
--- a/client/Android/Studio/freeRDPCore/src/main/cpp/android_jni_callback.c
+++ b/client/Android/Studio/freeRDPCore/src/main/cpp/android_jni_callback.c
@@ -201,7 +201,7 @@ finish:
 /* callback to freerdp class */
 void freerdp_callback(const char* callback, const char* signature, ...)
 {
-	va_list vl;
+	va_list vl = { 0 };
 	va_start(vl, signature);
 	java_callback_void(jLibFreeRDPObject, callback, signature, vl);
 	va_end(vl);
@@ -209,7 +209,7 @@ void freerdp_callback(const char* callback, const char* signature, ...)
 
 jboolean freerdp_callback_bool_result(const char* callback, const char* signature, ...)
 {
-	va_list vl;
+	va_list vl = { 0 };
 	va_start(vl, signature);
 	jboolean res = java_callback_bool(jLibFreeRDPObject, callback, signature, vl);
 	va_end(vl);
@@ -218,7 +218,7 @@ jboolean freerdp_callback_bool_result(const char* callback, const char* signatur
 
 jint freerdp_callback_int_result(const char* callback, const char* signature, ...)
 {
-	va_list vl;
+	va_list vl = { 0 };
 	va_start(vl, signature);
 	jint res = java_callback_int(jLibFreeRDPObject, callback, signature, vl);
 	va_end(vl);
diff --git a/client/SDL/SDL2/dialogs/sdl_connection_dialog.cpp b/client/SDL/SDL2/dialogs/sdl_connection_dialog.cpp
index 9ae26fe0e..55528906c 100644
--- a/client/SDL/SDL2/dialogs/sdl_connection_dialog.cpp
+++ b/client/SDL/SDL2/dialogs/sdl_connection_dialog.cpp
@@ -455,7 +455,7 @@ std::string SDLConnectionDialog::print(const char* fmt, va_list ap)
 		if (size > 0)
 			res.resize(WINPR_ASSERTING_INT_CAST(size_t, size));
 
-		va_list copy;
+		va_list copy = {};
 		va_copy(copy, ap);
 		WINPR_PRAGMA_DIAG_PUSH
 		WINPR_PRAGMA_DIAG_IGNORED_FORMAT_NONLITERAL
diff --git a/client/SDL/SDL3/dialogs/sdl_connection_dialog.cpp b/client/SDL/SDL3/dialogs/sdl_connection_dialog.cpp
index 2ac984aab..8fd501ce9 100644
--- a/client/SDL/SDL3/dialogs/sdl_connection_dialog.cpp
+++ b/client/SDL/SDL3/dialogs/sdl_connection_dialog.cpp
@@ -439,7 +439,7 @@ std::string SDLConnectionDialog::print(const char* fmt, va_list ap)
 		if (size > 0)
 			res.resize(WINPR_ASSERTING_INT_CAST(uint32_t, size));
 
-		va_list copy;
+		va_list copy = {};
 		va_copy(copy, ap);
 		WINPR_PRAGMA_DIAG_PUSH
 		WINPR_PRAGMA_DIAG_IGNORED_FORMAT_NONLITERAL
diff --git a/client/SDL/SDL3/dialogs/sdl_connection_dialog_wrapper.cpp b/client/SDL/SDL3/dialogs/sdl_connection_dialog_wrapper.cpp
index b632833a6..e04b0bf32 100644
--- a/client/SDL/SDL3/dialogs/sdl_connection_dialog_wrapper.cpp
+++ b/client/SDL/SDL3/dialogs/sdl_connection_dialog_wrapper.cpp
@@ -75,7 +75,7 @@ bool SdlConnectionDialogWrapper::handleEvent(const SDL_Event& event)
 WINPR_ATTR_FORMAT_ARG(1, 0)
 static std::string format(WINPR_FORMAT_ARG const char* fmt, va_list ap)
 {
-	va_list ap1;
+	va_list ap1 = {};
 	va_copy(ap1, ap);
 	const int size = vsnprintf(nullptr, 0, fmt, ap1);
 	va_end(ap1);
@@ -86,7 +86,7 @@ static std::string format(WINPR_FORMAT_ARG const char* fmt, va_list ap)
 	std::string msg;
 	msg.resize(static_cast<size_t>(size) + 1);
 
-	va_list ap2;
+	va_list ap2 = {};
 	va_copy(ap2, ap);
 	std::ignore = vsnprintf(msg.data(), msg.size(), fmt, ap2);
 	va_end(ap2);
@@ -95,7 +95,7 @@ static std::string format(WINPR_FORMAT_ARG const char* fmt, va_list ap)
 
 void SdlConnectionDialogWrapper::setTitle(const char* fmt, ...)
 {
-	va_list ap;
+	va_list ap = {};
 	va_start(ap, fmt);
 	setTitle(format(fmt, ap));
 	va_end(ap);
@@ -108,7 +108,7 @@ void SdlConnectionDialogWrapper::setTitle(const std::string& title)
 
 void SdlConnectionDialogWrapper::showInfo(const char* fmt, ...)
 {
-	va_list ap;
+	va_list ap = {};
 	va_start(ap, fmt);
 	showInfo(format(fmt, ap));
 	va_end(ap);
@@ -121,7 +121,7 @@ void SdlConnectionDialogWrapper::showInfo(const std::string& info)
 
 void SdlConnectionDialogWrapper::showWarn(const char* fmt, ...)
 {
-	va_list ap;
+	va_list ap = {};
 	va_start(ap, fmt);
 	showWarn(format(fmt, ap));
 	va_end(ap);
@@ -134,7 +134,7 @@ void SdlConnectionDialogWrapper::showWarn(const std::string& info)
 
 void SdlConnectionDialogWrapper::showError(const char* fmt, ...)
 {
-	va_list ap;
+	va_list ap = {};
 	va_start(ap, fmt);
 	showError(format(fmt, ap));
 	va_end(ap);
diff --git a/client/Windows/wf_client.c b/client/Windows/wf_client.c
index c9054a0e4..44ae0ae16 100644
--- a/client/Windows/wf_client.c
+++ b/client/Windows/wf_client.c
@@ -663,8 +663,8 @@ static WCHAR* wf_format_text(const WCHAR* fmt, ...)
 
 	do
 	{
-		WCHAR* tmp;
-		va_list ap;
+		WCHAR* tmp = NULL;
+		va_list ap = { 0 };
 		va_start(ap, fmt);
 		rc = _vsnwprintf(buffer, size, fmt, ap);
 		va_end(ap);
diff --git a/client/X11/xf_utils.c b/client/X11/xf_utils.c
index 99a3e4c93..f47e5bb32 100644
--- a/client/X11/xf_utils.c
+++ b/client/X11/xf_utils.c
@@ -90,7 +90,7 @@ static int write_result_log_expect_success(wLog* log, DWORD level, const char* f
 {
 	if (rc != Success)
 	{
-		va_list ap;
+		va_list ap = { 0 };
 		(void)write_result_log_va(log, level, fname, fkt, line, display, name, rc, 0, ap);
 	}
 	return rc;
@@ -101,7 +101,7 @@ static int write_result_log_expect_one(wLog* log, DWORD level, const char* fname
 {
 	if (rc != 1)
 	{
-		va_list ap;
+		va_list ap = { 0 };
 		(void)write_result_log_va(log, level, fname, fkt, line, display, name, rc, 0, ap);
 	}
 	return rc;
diff --git a/client/X11/xf_window.c b/client/X11/xf_window.c
index b4138bbbf..d67e7d574 100644
--- a/client/X11/xf_window.c
+++ b/client/X11/xf_window.c
@@ -232,7 +232,7 @@ static void xf_SetWindowTitleText(xfContext* xfc, Window window, const char* nam
 void xf_SendClientEvent(xfContext* xfc, Window window, Atom atom, unsigned int numArgs, ...)
 {
 	XEvent xevent = { 0 };
-	va_list argp;
+	va_list argp = { 0 };
 	va_start(argp, numArgs);
 
 	xevent.xclient.type = ClientMessage;
diff --git a/client/common/client.c b/client/common/client.c
index cb34b0d6a..93dedc543 100644
--- a/client/common/client.c
+++ b/client/common/client.c
@@ -2203,7 +2203,7 @@ BOOL freerdp_client_handle_pen(rdpClientContext* cctx, UINT32 flags, INT32 devic
 #if defined(CHANNEL_RDPEI_CLIENT)
 	if ((flags & FREERDP_PEN_REGISTER) != 0)
 	{
-		va_list args;
+		va_list args = { 0 };
 
 		va_start(args, deviceid);
 		double pressure = va_arg(args, double);
@@ -2231,7 +2231,7 @@ BOOL freerdp_client_handle_pen(rdpClientContext* cctx, UINT32 flags, INT32 devic
 	UINT16 rotation = 0;
 	INT16 tiltX = 0;
 	INT16 tiltY = 0;
-	va_list args;
+	va_list args = { 0 };
 	va_start(args, deviceid);
 
 	x = va_arg(args, INT32);
@@ -2572,7 +2572,7 @@ char* freerdp_client_get_aad_url(rdpClientContext* cctx, freerdp_client_aad_type
 	WINPR_ASSERT(cctx);
 	char* str = NULL;
 
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, type);
 	switch (type)
 	{
diff --git a/client/common/client_cliprdr_file.c b/client/common/client_cliprdr_file.c
index b594bc0ec..3b87490cf 100644
--- a/client/common/client_cliprdr_file.c
+++ b/client/common/client_cliprdr_file.c
@@ -228,7 +228,7 @@ static CliprdrFuseFile* fuse_file_new(WINPR_FORMAT_ARG const char* fmt, ...)
 	WINPR_ASSERT(fmt);
 
 	{
-		va_list ap;
+		va_list ap = { 0 };
 		va_start(ap, fmt);
 		const int rc =
 		    winpr_vasprintf(&file->filename_with_root, &file->filename_with_root_len, fmt, ap);
diff --git a/client/common/sso_mib_tokens.c b/client/common/sso_mib_tokens.c
index 9a3bf0165..16ed39e0e 100644
--- a/client/common/sso_mib_tokens.c
+++ b/client/common/sso_mib_tokens.c
@@ -153,7 +153,7 @@ static BOOL sso_mib_get_access_token(rdpContext* context, AccessTokenType tokenT
 	const char* scope = NULL;
 	const char* req_cnf = NULL;
 
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, count);
 
 	if (tokenType == ACCESS_TOKEN_TYPE_AAD)
diff --git a/client/iOS/Models/RDPSession.m b/client/iOS/Models/RDPSession.m
index 9a844cc23..d6b6535ae 100644
--- a/client/iOS/Models/RDPSession.m
+++ b/client/iOS/Models/RDPSession.m
@@ -46,7 +46,7 @@ NSString *TSXSessionDidFailToConnectNotification = @"TSXSessionDidFailToConnect"
 
 static BOOL addArgument(int *argc, char ***argv, const char *fmt, ...)
 {
-	va_list ap;
+	va_list ap = { 0 };
 	char *arg = NULL;
 	char **tmp = realloc(*argv, (*argc + 1) * sizeof(char *));
 
diff --git a/libfreerdp/core/credssp_auth.c b/libfreerdp/core/credssp_auth.c
index 0a488da46..18bd5c8e0 100644
--- a/libfreerdp/core/credssp_auth.c
+++ b/libfreerdp/core/credssp_auth.c
@@ -108,7 +108,7 @@ static BOOL log_status_(SECURITY_STATUS status, DWORD level, const char* file, c
 	if (WLog_IsLevelActive(log, level))
 	{
 		char fwhat[128] = { 0 };
-		va_list ap;
+		va_list ap = { 0 };
 		va_start(ap, what);
 		(void)vsnprintf(fwhat, sizeof(fwhat) - 1, what, ap);
 		va_end(ap);
diff --git a/libfreerdp/core/freerdp.c b/libfreerdp/core/freerdp.c
index 7cd87be3f..43426afe5 100644
--- a/libfreerdp/core/freerdp.c
+++ b/libfreerdp/core/freerdp.c
@@ -807,7 +807,7 @@ static BOOL freerdp_common_context(rdpContext* context, AccessTokenType tokenTyp
 	if (!context->instance || !context->instance->GetAccessToken)
 		return TRUE;
 
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, count);
 	switch (tokenType)
 	{
diff --git a/libfreerdp/core/gateway/http.c b/libfreerdp/core/gateway/http.c
index a76e474f5..849bff7cd 100644
--- a/libfreerdp/core/gateway/http.c
+++ b/libfreerdp/core/gateway/http.c
@@ -271,7 +271,7 @@ WINPR_ATTR_FORMAT_ARG(2, 0)
 static BOOL list_append(HttpContext* context, WINPR_FORMAT_ARG const char* str, va_list ap)
 {
 	BOOL rc = FALSE;
-	va_list vat;
+	va_list vat = { 0 };
 	char* Pragma = NULL;
 	size_t PragmaSize = 0;
 
@@ -1703,7 +1703,7 @@ FREERDP_LOCAL BOOL http_context_set_header(HttpContext* context, const char* key
                                            ...)
 {
 	WINPR_ASSERT(context);
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, value);
 	const BOOL rc = http_context_set_header_va(context, key, value, ap);
 	va_end(ap);
@@ -1715,7 +1715,7 @@ BOOL http_request_set_header(HttpRequest* request, const char* key, const char*
 	WINPR_ASSERT(request);
 	char* v = NULL;
 	size_t vlen = 0;
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, value);
 	winpr_vasprintf(&v, &vlen, value, ap);
 	va_end(ap);
diff --git a/libfreerdp/core/test/TestSettings.c b/libfreerdp/core/test/TestSettings.c
index 657dc4583..2e870ddba 100644
--- a/libfreerdp/core/test/TestSettings.c
+++ b/libfreerdp/core/test/TestSettings.c
@@ -15,7 +15,7 @@
 static void log_start_(const char* fkt, ...)
 {
 	(void)fprintf(stderr, "TestSettings [");
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, fkt);
 	(void)vfprintf(stderr, fkt, ap);
 	va_end(ap);
@@ -27,7 +27,7 @@ static void log_start_(const char* fkt, ...)
 static BOOL log_result_(BOOL value, const char* fkt, ...)
 {
 	(void)fprintf(stderr, "TestSettings [");
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, fkt);
 	(void)vfprintf(stderr, fkt, ap);
 	va_end(ap);
diff --git a/libfreerdp/crypto/privatekey.c b/libfreerdp/crypto/privatekey.c
index 0e2740e49..c092bba11 100644
--- a/libfreerdp/crypto/privatekey.c
+++ b/libfreerdp/crypto/privatekey.c
@@ -408,7 +408,7 @@ BOOL freerdp_key_generate(rdpPrivateKey* key, const char* type, size_t count, ..
 		WLog_ERR(TAG, "Argument type=%s requires count=1, got %" PRIuz ", aborting", type, count);
 		return FALSE;
 	}
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, count);
 	const int key_length = va_arg(ap, int);
 	va_end(ap);
diff --git a/server/proxy/channels/pf_channel_drdynvc.c b/server/proxy/channels/pf_channel_drdynvc.c
index b3d5e226d..317211ee4 100644
--- a/server/proxy/channels/pf_channel_drdynvc.c
+++ b/server/proxy/channels/pf_channel_drdynvc.c
@@ -136,7 +136,7 @@ static void dyn_log_(wLog* log, DWORD level, const pServerDynamicChannelContext*
 	                     getDirection(isBackData), channelName, drdynvc_get_packet_type(cmd),
 	                     channelId);
 
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, fmt);
 	(void)winpr_vasprintf(&msg, &msglen, fmt, ap);
 	va_end(ap);
diff --git a/uwac/libuwac/uwac-display.c b/uwac/libuwac/uwac-display.c
index 9bc602aa5..fe9f232be 100644
--- a/uwac/libuwac/uwac-display.c
+++ b/uwac/libuwac/uwac-display.c
@@ -54,7 +54,7 @@ static const char* event_names[] = {
 static bool uwac_default_error_handler(UwacDisplay* display, UwacReturnCode code, const char* msg,
                                        ...)
 {
-	va_list args;
+	va_list args = { 0 };
 	va_start(args, msg);
 	(void)vfprintf(stderr, "%s", args);
 	va_end(args);
diff --git a/winpr/include/winpr/platform.h b/winpr/include/winpr/platform.h
index 17990104c..681cb5d5a 100644
--- a/winpr/include/winpr/platform.h
+++ b/winpr/include/winpr/platform.h
@@ -594,7 +594,7 @@ WINPR_PRAGMA_DIAG_POP
 #if defined(__GNUC__) || defined(__clang__)
 #define WINPR_ATTR_FORMAT_ARG(pos, args) __attribute__((__format__(__printf__, pos, args)))
 #define WINPR_FORMAT_ARG /**/
-#else
+#elif defined(_MSC_VER)
 #define WINPR_ATTR_FORMAT_ARG(pos, args)
 #define WINPR_FORMAT_ARG _Printf_format_string_
 #endif
diff --git a/winpr/include/winpr/wlog.h b/winpr/include/winpr/wlog.h
index f9b0e3a35..765822187 100644
--- a/winpr/include/winpr/wlog.h
+++ b/winpr/include/winpr/wlog.h
@@ -273,7 +273,11 @@ extern "C"
 
 		if (WLog_IsLevelActive(log_cached_ptr, log_level))
 		{
-			va_list ap;
+#if defined(__cplusplus)
+			va_list ap = {};
+#else
+		    va_list ap = { 0 };
+#endif
 			va_start(ap, fmt);
 			WLog_PrintTextMessageVA(log_cached_ptr, log_level, line, file, fkt, fmt, ap);
 			va_end(ap);
diff --git a/winpr/libwinpr/path/path.c b/winpr/libwinpr/path/path.c
index 66afcd9d8..04ec0e690 100644
--- a/winpr/libwinpr/path/path.c
+++ b/winpr/libwinpr/path/path.c
@@ -1258,7 +1258,7 @@ char* winpr_GetConfigFilePath(BOOL system, const char* filename)
 
 char* winpr_GetConfigFilePathV(BOOL system, const char* filename, ...)
 {
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, filename);
 	char* str = winpr_GetConfigFilePathVA(system, filename, ap);
 	va_end(ap);
diff --git a/winpr/libwinpr/path/shell.c b/winpr/libwinpr/path/shell.c
index 2d7630741..e3fce3423 100644
--- a/winpr/libwinpr/path/shell.c
+++ b/winpr/libwinpr/path/shell.c
@@ -401,7 +401,7 @@ char* GetKnownSubPath(eKnownPathTypes id, const char* path)
 
 char* GetKnownSubPathV(eKnownPathTypes id, const char* path, ...)
 {
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, path);
 	char* str = GetKnownSubPathVA(id, path, ap);
@@ -455,7 +455,7 @@ char* GetEnvironmentSubPath(char* name, const char* path)
 
 char* GetEnvironmentSubPathV(char* name, const char* path, ...)
 {
-	va_list ap;
+	va_list ap = { 0 };
 	va_start(ap, path);
 	char* str = GetEnvironmentSubPathVA(name, path, ap);
 	va_end(ap);
@@ -483,7 +483,7 @@ char* GetCombinedPath(const char* basePath, const char* subPathFmt)
 
 char* GetCombinedPathV(const char* basePath, const char* subPathFmt, ...)
 {
-	va_list ap;
+	va_list ap = { 0 };
 
 	va_start(ap, subPathFmt);
 	char* str = GetCombinedPathVA(basePath, subPathFmt, ap);
diff --git a/winpr/libwinpr/utils/collections/ArrayList.c b/winpr/libwinpr/utils/collections/ArrayList.c
index 55ccd64a9..1aa0de8f5 100644
--- a/winpr/libwinpr/utils/collections/ArrayList.c
+++ b/winpr/libwinpr/utils/collections/ArrayList.c
@@ -546,7 +546,7 @@ BOOL ArrayList_ForEach(wArrayList* arrayList, ArrayList_ForEachFkt fkt, ...)
 BOOL ArrayList_ForEachAP(wArrayList* arrayList, ArrayList_ForEachFkt fkt, va_list ap)
 {
 	BOOL rc = FALSE;
-	va_list cap;
+	va_list cap = { 0 };
 
 	WINPR_ASSERT(arrayList);
 	WINPR_ASSERT(fkt);
diff --git a/winpr/libwinpr/utils/stream.c b/winpr/libwinpr/utils/stream.c
index 4493249e9..94ed656d7 100644
--- a/winpr/libwinpr/utils/stream.c
+++ b/winpr/libwinpr/utils/stream.c
@@ -312,7 +312,7 @@ BOOL Stream_CheckAndLogRequiredCapacityEx(const char* tag, DWORD level, wStream*
 
 	if (actual < nmemb)
 	{
-		va_list args;
+		va_list args = { 0 };
 
 		va_start(args, fmt);
 		Stream_CheckAndLogRequiredCapacityExVa(tag, level, s, nmemb, size, fmt, args);
@@ -370,7 +370,7 @@ BOOL Stream_CheckAndLogRequiredCapacityWLogEx(wLog* log, DWORD level, wStream* s
 
 	if (actual < nmemb)
 	{
-		va_list args;
+		va_list args = { 0 };
 
 		va_start(args, fmt);
 		Stream_CheckAndLogRequiredCapacityWLogExVa(log, level, s, nmemb, size, fmt, args);
@@ -390,7 +390,7 @@ BOOL Stream_CheckAndLogRequiredLengthEx(const char* tag, DWORD level, wStream* s
 
 	if (actual < nmemb)
 	{
-		va_list args;
+		va_list args = { 0 };
 
 		va_start(args, fmt);
 		Stream_CheckAndLogRequiredLengthExVa(tag, level, s, nmemb, size, fmt, args);
@@ -421,7 +421,7 @@ BOOL Stream_CheckAndLogRequiredLengthWLogEx(wLog* log, DWORD level, wStream* s,
 
 	if (actual < nmemb)
 	{
-		va_list args;
+		va_list args = { 0 };
 
 		va_start(args, fmt);
 		Stream_CheckAndLogRequiredLengthWLogExVa(log, level, s, nmemb, size, fmt, args);
diff --git a/winpr/libwinpr/utils/wlog/Layout.c b/winpr/libwinpr/utils/wlog/Layout.c
index 2374d7838..f8927d5b3 100644
--- a/winpr/libwinpr/utils/wlog/Layout.c
+++ b/winpr/libwinpr/utils/wlog/Layout.c
@@ -91,7 +91,7 @@ WINPR_ATTR_FORMAT_ARG(3, 4)
 static void WLog_PrintMessagePrefix(char* prefix, size_t prefixlen,
                                     WINPR_FORMAT_ARG const char* format, ...)
 {
-	va_list args;
+	va_list args = { 0 };
 	va_start(args, format);
 	WLog_PrintMessagePrefixVA(prefix, prefixlen, format, args);
 	va_end(args);
diff --git a/winpr/libwinpr/utils/wlog/wlog.c b/winpr/libwinpr/utils/wlog/wlog.c
index e70fd22f7..73dbd477e 100644
--- a/winpr/libwinpr/utils/wlog/wlog.c
+++ b/winpr/libwinpr/utils/wlog/wlog.c
@@ -429,7 +429,7 @@ BOOL WLog_PrintMessage(wLog* log, DWORD type, DWORD level, size_t line, const ch
                        const char* function, ...)
 {
 	BOOL status = 0;
-	va_list args;
+	va_list args = { 0 };
 	va_start(args, function);
 	status = WLog_PrintMessageVA(log, type, level, line, file, function, args);
 	va_end(args);
@@ -440,7 +440,7 @@ BOOL WLog_PrintTextMessage(wLog* log, DWORD level, size_t line, const char* file
                            const char* function, const char* fmt, ...)
 {
 	BOOL status = 0;
-	va_list args;
+	va_list args = { 0 };
 	va_start(args, fmt);
 	status = WLog_PrintTextMessageVA(log, level, line, file, function, fmt, args);
 	va_end(args);