diff --git a/php/ext/google/protobuf/php-upb.c b/php/ext/google/protobuf/php-upb.c
index 180b2a9b8660..55bedc6043f4 100644
--- a/php/ext/google/protobuf/php-upb.c
+++ b/php/ext/google/protobuf/php-upb.c
@@ -3082,7 +3082,8 @@ static upb_MessageValue jsondec_int(jsondec* d, const upb_FieldDef* f) {
 
 /* Parse UINT32 or UINT64 value. */
 static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER: {
@@ -3119,7 +3120,8 @@ static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
 /* Parse DOUBLE or FLOAT value. */
 static upb_MessageValue jsondec_double(jsondec* d, const upb_FieldDef* f) {
   upb_StringView str;
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER:
@@ -15767,7 +15769,8 @@ bool upb_Message_Next(const upb_Message* msg, const upb_MessageDef* m,
   const upb_MiniTable* mt = upb_MessageDef_MiniTable(m);
   size_t i = *iter;
   size_t n = upb_MiniTable_FieldCount(mt);
-  const upb_MessageValue zero = {0};
+  upb_MessageValue zero;
+  memset(&zero, 0, sizeof(zero));
   UPB_UNUSED(ext_pool);
 
   // Iterate over normal fields, returning the first one that is set.
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index 4eaaefe88d66..a8d241261493 100644
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -2570,7 +2570,8 @@ static upb_MessageValue jsondec_int(jsondec* d, const upb_FieldDef* f) {
 
 /* Parse UINT32 or UINT64 value. */
 static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER: {
@@ -2607,7 +2608,8 @@ static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
 /* Parse DOUBLE or FLOAT value. */
 static upb_MessageValue jsondec_double(jsondec* d, const upb_FieldDef* f) {
   upb_StringView str;
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER:
@@ -15255,7 +15257,8 @@ bool upb_Message_Next(const upb_Message* msg, const upb_MessageDef* m,
   const upb_MiniTable* mt = upb_MessageDef_MiniTable(m);
   size_t i = *iter;
   size_t n = upb_MiniTable_FieldCount(mt);
-  const upb_MessageValue zero = {0};
+  upb_MessageValue zero;
+  memset(&zero, 0, sizeof(zero));
   UPB_UNUSED(ext_pool);
 
   // Iterate over normal fields, returning the first one that is set.
diff --git a/upb/json/decode.c b/upb/json/decode.c
index 8fe655ccfddf..5659a017aac8 100644
--- a/upb/json/decode.c
+++ b/upb/json/decode.c
@@ -711,7 +711,8 @@ static upb_MessageValue jsondec_int(jsondec* d, const upb_FieldDef* f) {
 
 /* Parse UINT32 or UINT64 value. */
 static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER: {
@@ -748,7 +749,8 @@ static upb_MessageValue jsondec_uint(jsondec* d, const upb_FieldDef* f) {
 /* Parse DOUBLE or FLOAT value. */
 static upb_MessageValue jsondec_double(jsondec* d, const upb_FieldDef* f) {
   upb_StringView str;
-  upb_MessageValue val = {0};
+  upb_MessageValue val;
+  memset(&val, 0, sizeof(val));
 
   switch (jsondec_peek(d)) {
     case JD_NUMBER:
diff --git a/upb/reflection/message.c b/upb/reflection/message.c
index 285418295a2e..f47a777bf46e 100644
--- a/upb/reflection/message.c
+++ b/upb/reflection/message.c
@@ -138,7 +138,8 @@ bool upb_Message_Next(const upb_Message* msg, const upb_MessageDef* m,
   const upb_MiniTable* mt = upb_MessageDef_MiniTable(m);
   size_t i = *iter;
   size_t n = upb_MiniTable_FieldCount(mt);
-  const upb_MessageValue zero = {0};
+  upb_MessageValue zero;
+  memset(&zero, 0, sizeof(zero));
   UPB_UNUSED(ext_pool);
 
   // Iterate over normal fields, returning the first one that is set.