diff --git a/src/internal.c b/src/internal.c
index 067b7a6c08..f90e07c2b9 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -25909,6 +25909,10 @@ int SendCertificateStatus(WOLFSSL* ssl)
 
                         if (idx > chain->length)
                             break;
+                        if ((i + 1) >= MAX_CERT_EXTENSIONS) {
+                            ret = MAX_CERT_EXTENSIONS_ERR;
+                            break;
+                        }
                         ret = CreateOcspRequest(ssl, request, cert, der.buffer,
                                                 der.length, &ctxOwnsRequest);
                         if (ret == 0) {
@@ -25937,6 +25941,11 @@ int SendCertificateStatus(WOLFSSL* ssl)
             else {
                 while (ret == 0 &&
                             NULL != (request = ssl->ctx->chainOcspRequest[i])) {
+                    if ((i + 1) >= MAX_CERT_EXTENSIONS) {
+                        ret = MAX_CERT_EXTENSIONS_ERR;
+                        break;
+                    }
+
                     request->ssl = ssl;
                     ret = CheckOcspRequest(SSL_CM(ssl)->ocsp_stapling,
                                            request, &responses[++i], ssl->heap);
diff --git a/src/sniffer.c b/src/sniffer.c
index e8664721b1..c00915070b 100644
--- a/src/sniffer.c
+++ b/src/sniffer.c
@@ -4195,6 +4195,9 @@ static int ProcessClientHello(const byte* input, int* sslBytes,
         {
             word16 listLen = 0, offset = 0;
 
+            if (extLen < OPAQUE16_LEN)
+                return BUFFER_ERROR;
+
             ato16(input + offset, &listLen);
             offset += OPAQUE16_LEN;
 
@@ -4228,7 +4231,13 @@ static int ProcessClientHello(const byte* input, int* sslBytes,
     #ifdef WOLFSSL_TLS13
         case EXT_KEY_SHARE:
         {
-            word16 ksLen = (word16)((input[0] << 8) | input[1]);
+            word16 ksLen = 0;
+            if (extLen < OPAQUE16_LEN) {
+                SetError(BUFFER_ERROR_STR, error, session, FATAL_ERROR_STATE);
+                return BUFFER_ERROR;
+            }
+
+            ksLen = (word16)((input[0] << 8) | input[1]);
             if (ksLen + OPAQUE16_LEN > extLen) {
                 SetError(CLIENT_HELLO_INPUT_STR, error, session, FATAL_ERROR_STATE);
                 return WOLFSSL_FATAL_ERROR;
@@ -4252,6 +4261,11 @@ static int ProcessClientHello(const byte* input, int* sslBytes,
             word32 ticketAge;
             const byte *identity, *binders;
 
+            if (extLen < OPAQUE16_LEN) {
+                SetError(BUFFER_ERROR_STR, error, session, FATAL_ERROR_STATE);
+                return BUFFER_ERROR;
+            }
+
             idsLen = (word16)((input[idx] << 8) | input[idx+1]);
             if ((word32)idsLen + OPAQUE16_LEN + idx > (word32)extLen) {
                 SetError(CLIENT_HELLO_INPUT_STR, error, session, FATAL_ERROR_STATE);
diff --git a/src/tls.c b/src/tls.c
index b854b8f8cd..a329c935a6 100644
--- a/src/tls.c
+++ b/src/tls.c
@@ -2800,6 +2800,9 @@ int TLSX_SNI_GetFromBuffer(const byte* clientHello, word32 helloSz,
         } else {
             word16 listLen;
 
+            if (extLen < OPAQUE16_LEN)
+                return BUFFER_ERROR;
+
             ato16(clientHello + offset, &listLen);
             offset += OPAQUE16_LEN;
 
@@ -3611,6 +3614,14 @@ int ProcessChainOCSPRequest(WOLFSSL* ssl)
 
     if (chain && chain->buffer) {
         while (ret == 0 && pos + OPAQUE24_LEN < chain->length) {
+            if (i >= MAX_CERT_EXTENSIONS) {
+                WOLFSSL_MSG_EX(
+                    "OCSP request cert chain exceeds maximum length: "
+                    "i=%d, MAX_CERT_EXTENSIONS=%d", i, MAX_CERT_EXTENSIONS);
+                ret = MAX_CERT_EXTENSIONS_ERR;
+                break;
+            }
+
             c24to32(chain->buffer + pos, &der.length);
             pos += OPAQUE24_LEN;
             der.buffer = chain->buffer + pos;
diff --git a/src/tls13.c b/src/tls13.c
index a591532be2..573751c4b9 100644
--- a/src/tls13.c
+++ b/src/tls13.c
@@ -8871,7 +8871,7 @@ static word32 NextCert(byte* data, word32 length, word32* idx)
  * extIdx    The index number of certificate status request data
  *           for the certificate.
  * offset    index offset
- * returns   Total number of bytes written.
+ * returns   Total number of bytes written on success or negative value on error.
  */
 static int WriteCSRToBuffer(WOLFSSL* ssl, DerBuffer** certExts,
                                 word16* extSz,  word16 extSz_num)
@@ -8886,6 +8886,9 @@ static int WriteCSRToBuffer(WOLFSSL* ssl, DerBuffer** certExts,
     word32 extIdx;
     DerBuffer* der;
 
+    if (extSz_num > MAX_CERT_EXTENSIONS)
+        return MAX_CERT_EXTENSIONS_ERR;
+
     ext = TLSX_Find(ssl->extensions, TLSX_STATUS_REQUEST);
     csr = ext ? (CertificateStatusRequest*)ext->data : NULL;
 
@@ -9137,8 +9140,11 @@ static int SendTls13Certificate(WOLFSSL* ssl)
             if (ret != 0)
                 return ret;
 
-            ret = WriteCSRToBuffer(ssl, &ssl->buffers.certExts[0], &extSz[0],
-                    1 /* +1 for leaf */ + (word16)ssl->buffers.certChainCnt);
+            if ((1 + ssl->buffers.certChainCnt) > MAX_CERT_EXTENSIONS)
+                ret = MAX_CERT_EXTENSIONS_ERR;
+            if (ret == 0)
+                ret = WriteCSRToBuffer(ssl, &ssl->buffers.certExts[0], &extSz[0],
+                        1 /* +1 for leaf */ + (word16)ssl->buffers.certChainCnt);
             if (ret < 0)
                 return ret;
             totalextSz += ret;