diff --git a/src/ssl.c b/src/ssl.c
index c2a5827c9d..db42d6bb9b 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -15398,20 +15398,20 @@ WOLFSSL_BUF_MEM* wolfSSL_BUF_MEM_new(void)
 int wolfSSL_BUF_MEM_grow_ex(WOLFSSL_BUF_MEM* buf, size_t len,
         char zeroFill)
 {
-
-    int len_int = (int)len;
-    int mx;
+    size_t mx;
     char* tmp;
 
-    /* verify provided arguments */
-    if (buf == NULL || len_int < 0) {
+    /* verify provided arguments. The return value is an int holding the
+     * resulting length, so reject any len that cannot be represented as a
+     * non-negative int. This also prevents truncating size_t to int. */
+    if (buf == NULL || len > (size_t)INT_MAX) {
         return 0; /* BAD_FUNC_ARG; */
     }
 
     /* check to see if fits in existing length */
     if (buf->length > len) {
         buf->length = len;
-        return len_int;
+        return (int)len;
     }
 
     /* check to see if fits in max buffer */
@@ -15420,16 +15420,19 @@ int wolfSSL_BUF_MEM_grow_ex(WOLFSSL_BUF_MEM* buf, size_t len,
             XMEMSET(&buf->data[buf->length], 0, len - buf->length);
         }
         buf->length = len;
-        return len_int;
+        return (int)len;
     }
 
     /* expand size, to handle growth */
-    mx = (len_int + 3) / 3 * 4;
+    mx = (len + 3) / 3 * 4;
 
 #ifdef WOLFSSL_NO_REALLOC
     tmp = (char*)XMALLOC(mx, NULL, DYNAMIC_TYPE_OPENSSL);
     if (tmp != NULL && buf->data != NULL) {
-       XMEMCPY(tmp, buf->data, len_int);
+       /* Only buf->length bytes of the old buffer are valid; copying len
+        * bytes here would over-read the old allocation since this branch is
+        * only reached when buf->max < len. */
+       XMEMCPY(tmp, buf->data, buf->length);
        XFREE(buf->data, NULL, DYNAMIC_TYPE_OPENSSL);
        buf->data = NULL;
     }
@@ -15443,12 +15446,12 @@ int wolfSSL_BUF_MEM_grow_ex(WOLFSSL_BUF_MEM* buf, size_t len,
     }
     buf->data = tmp;
 
-    buf->max = (size_t)mx;
+    buf->max = mx;
     if (zeroFill)
         XMEMSET(&buf->data[buf->length], 0, len - buf->length);
     buf->length = len;
 
-    return len_int;
+    return (int)len;
 
 }
 
@@ -15462,10 +15465,11 @@ int wolfSSL_BUF_MEM_grow(WOLFSSL_BUF_MEM* buf, size_t len)
 int wolfSSL_BUF_MEM_resize(WOLFSSL_BUF_MEM* buf, size_t len)
 {
     char* tmp;
-    int mx;
+    size_t mx;
 
-    /* verify provided arguments */
-    if (buf == NULL || len == 0 || (int)len <= 0) {
+    /* verify provided arguments. The return value is an int, so reject any
+     * len that cannot be represented as a positive int. */
+    if (buf == NULL || len == 0 || len > (size_t)INT_MAX) {
         return 0; /* BAD_FUNC_ARG; */
     }
 
@@ -15476,7 +15480,7 @@ int wolfSSL_BUF_MEM_resize(WOLFSSL_BUF_MEM* buf, size_t len)
         return wolfSSL_BUF_MEM_grow_ex(buf, len, 0);
 
     /* expand size, to handle growth */
-    mx = ((int)len + 3) / 3 * 4;
+    mx = (len + 3) / 3 * 4;
 
     /* We want to shrink the internal buffer */
 #ifdef WOLFSSL_NO_REALLOC
@@ -15496,7 +15500,7 @@ int wolfSSL_BUF_MEM_resize(WOLFSSL_BUF_MEM* buf, size_t len)
 
     buf->data = tmp;
     buf->length = len;
-    buf->max = (size_t)mx;
+    buf->max = mx;
 
     return (int)len;
 }
diff --git a/src/wolfio.c b/src/wolfio.c
index 4ebff95c69..30d2022de4 100644
--- a/src/wolfio.c
+++ b/src/wolfio.c
@@ -1710,6 +1710,12 @@ int wolfIO_DecodeUrl(const char* url, int urlSz, char* outName, char* outPath,
                     outName[i] = url[cur];
                 i++; cur++;
             }
+            /* A bracketed IPv6 literal must be terminated by ']'. The loop
+             * above can also stop on end-of-buffer, NUL, or the length cap,
+             * none of which represent a well-formed host. Reject those cases
+             * rather than accepting the unterminated tail as the hostname. */
+            if (cur >= urlSz || url[cur] != ']')
+                return WOLFSSL_FATAL_ERROR;
             cur++; /* skip ']' */
         }
         else {
@@ -1725,7 +1731,7 @@ int wolfIO_DecodeUrl(const char* url, int urlSz, char* outName, char* outPath,
         /* Need to pick out the path after the domain name */
 
         if (cur < urlSz && url[cur] == ':') {
-            char port[6];
+            char port[5];
             int j;
             word32 bigPort = 0;
             i = 0;
@@ -1733,15 +1739,27 @@ int wolfIO_DecodeUrl(const char* url, int urlSz, char* outName, char* outPath,
 
             XMEMSET(port, 0, sizeof(port));
 
-            while (i < 6 && cur < urlSz && url[cur] != 0 && url[cur] != '/') {
+            while (i < 5 && cur < urlSz && url[cur] != 0 && url[cur] != '/') {
                 port[i] = url[cur];
                 i++; cur++;
             }
 
+            /* A valid port is at most 5 digits; if more characters remain
+             * before the path/terminator the port field is malformed (e.g.
+             * a 6-digit port) and must be rejected rather than parsed from a
+             * truncated digit string. */
+            if (cur < urlSz && url[cur] != 0 && url[cur] != '/')
+                return WOLFSSL_FATAL_ERROR;
+
             for (j = 0; j < i; j++) {
                 if (port[j] < '0' || port[j] > '9') return WOLFSSL_FATAL_ERROR;
                 bigPort = (bigPort * 10) + (word32)(port[j] - '0');
             }
+            /* Reject out-of-range ports rather than silently truncating to
+             * word16, which would otherwise wrap (e.g. 65536 -> 0) and
+             * connect to an unintended port. */
+            if (bigPort > 65535)
+                return WOLFSSL_FATAL_ERROR;
             if (outPort)
                 *outPort = (word16)bigPort;
         }
diff --git a/wolfcrypt/src/aes.c b/wolfcrypt/src/aes.c
index 8223bcc8fb..0b19e8e293 100644
--- a/wolfcrypt/src/aes.c
+++ b/wolfcrypt/src/aes.c
@@ -11023,6 +11023,9 @@ int WARN_UNUSED_RESULT AES_GCM_decrypt_C(
     ret = (ret & ~res);
     ret |= (res & WC_NO_ERR_TRACE(AES_GCM_AUTH_E));
 #endif
+    if (ret != 0) {
+        ForceZero(out, sz);
+    }
     return ret;
 }
 #elif (defined(__aarch64__) || defined(WOLFSSL_ARMASM_NO_HW_CRYPTO)) || \
diff --git a/wolfcrypt/src/chacha20_poly1305.c b/wolfcrypt/src/chacha20_poly1305.c
index e9e5bb80c4..2a8228adf4 100644
--- a/wolfcrypt/src/chacha20_poly1305.c
+++ b/wolfcrypt/src/chacha20_poly1305.c
@@ -74,7 +74,10 @@ int wc_ChaCha20Poly1305_Encrypt(
             inPlaintextLen);
     if (ret == 0)
         ret = wc_ChaCha20Poly1305_Final(aead, outAuthTag);
-
+    #ifdef WOLFSSL_SMALL_STACK
+    if (aead != NULL)
+    #endif
+        ForceZero(aead, sizeof(ChaChaPoly_Aead));
     WC_FREE_VAR_EX(aead, NULL, DYNAMIC_TYPE_TMP_BUFFER);
 
     return ret;
@@ -123,6 +126,7 @@ int wc_ChaCha20Poly1305_Decrypt(
         /* zero plaintext on error */
         ForceZero(outPlaintext, inCiphertextLen);
     }
+    ForceZero(aead, sizeof(ChaChaPoly_Aead));
     WC_FREE_VAR_EX(aead, NULL, DYNAMIC_TYPE_TMP_BUFFER);
 
     return ret;