diff --git a/src/rtp/audio_decoders.cpp b/src/rtp/audio_decoders.cpp
index 499ad0299..060d62edf 100644
--- a/src/rtp/audio_decoders.cpp
+++ b/src/rtp/audio_decoders.cpp
@@ -683,7 +683,7 @@ int decode_audio_frame(struct coded_data *cdata, void *pbuf_data, struct pbuf_st
                 }
 
                 unsigned int length;
-                char plaintext[cdata->data->data_len]; // plaintext will be actually shorter
+                char plaintext[RTP_MAX_PACKET_LEN]; // plaintext will be actually shorter
                 size_t main_hdr_len = PT_AUDIO_HAS_FEC(pt) ? sizeof(fec_payload_hdr_t) : sizeof(audio_payload_hdr_t);
                 if (PT_AUDIO_IS_ENCRYPTED(pt)) {
                         uint32_t encryption_hdr = ntohl(*(uint32_t *)(void *) (cdata->data->data + main_hdr_len));
diff --git a/src/rtp/video_decoders.cpp b/src/rtp/video_decoders.cpp
index acf097725..53081065f 100644
--- a/src/rtp/video_decoders.cpp
+++ b/src/rtp/video_decoders.cpp
@@ -1608,7 +1608,7 @@ int decode_video_frame(struct coded_data *cdata, void *decoder_data, struct pbuf
                         goto cleanup;
                 }
 
-                char plaintext[len]; // will be actually shorter
+                char plaintext[RTP_MAX_PACKET_LEN]; // will be actually shorter
                 if (PT_VIDEO_IS_ENCRYPTED(pt)) {
                         int data_len;
 
diff --git a/src/transmit.cpp b/src/transmit.cpp
index d617379ee..4d87682c9 100644
--- a/src/transmit.cpp
+++ b/src/transmit.cpp
@@ -716,7 +716,7 @@ tx_send_base(struct tx *tx, struct video_frame *frame, struct rtp *rtp_session,
                 char     *data     = tile->data + ntohl(rtp_hdr_packet[1]);
                 int       data_len = packet_sizes.at(i % packet_sizes.size());
 
-                char encrypted_data[data_len + MAX_CRYPTO_EXCEED];
+                char encrypted_data[RTP_MAX_PACKET_LEN + MAX_CRYPTO_EXCEED];
                 if (tx->encryption != nullptr) {
                         data_len = tx->enc_funcs->encrypt(
                             tx->encryption, data, data_len,
@@ -851,7 +851,7 @@ audio_tx_send_chan(struct tx *tx, struct rtp *rtp_session, uint32_t timestamp,
                 rtp_hdr[1] = htonl(pos);
                 pos += data_len;
 
-                char encrypted_data[data_len + MAX_CRYPTO_EXCEED];
+                char encrypted_data[RTP_MAX_PACKET_LEN + MAX_CRYPTO_EXCEED];
                 if (tx->encryption) {
                         data_len = tx->enc_funcs->encrypt(
                             tx->encryption, const_cast<char *>(data), data_len,