diff --git a/libavformat/bintext.c b/libavformat/bintext.c
index 3fab3e4f57..58db3cf71a 100644
--- a/libavformat/bintext.c
+++ b/libavformat/bintext.c
@@ -151,7 +151,7 @@ static int bintext_read_header(AVFormatContext *s)
     st->codec->codec_id    = CODEC_ID_BINTEXT;
 
     st->codec->extradata_size = 2;
-    st->codec->extradata = av_malloc(st->codec->extradata_size);
+    st->codec->extradata = av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!st->codec->extradata)
         return AVERROR(ENOMEM);
     st->codec->extradata[0] = 16;
@@ -208,7 +208,7 @@ static int xbin_read_header(AVFormatContext *s)
         st->codec->extradata_size += fontheight * (flags & 0x10 ? 512 : 256);
     st->codec->codec_id    = flags & 4 ? CODEC_ID_XBIN : CODEC_ID_BINTEXT;
 
-    st->codec->extradata = av_malloc(st->codec->extradata_size);
+    st->codec->extradata = av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!st->codec->extradata)
         return AVERROR(ENOMEM);
     st->codec->extradata[0] = fontheight;
@@ -242,7 +242,7 @@ static int adf_read_header(AVFormatContext *s)
     st->codec->codec_id    = CODEC_ID_BINTEXT;
 
     st->codec->extradata_size = 2 + 48 + 4096;
-    st->codec->extradata = av_malloc(st->codec->extradata_size);
+    st->codec->extradata = av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!st->codec->extradata)
         return AVERROR(ENOMEM);
     st->codec->extradata[0] = 16;
@@ -299,7 +299,7 @@ static int idf_read_header(AVFormatContext *s)
     st->codec->codec_id    = CODEC_ID_IDF;
 
     st->codec->extradata_size = 2 + 48 + 4096;
-    st->codec->extradata = av_malloc(st->codec->extradata_size);
+    st->codec->extradata = av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!st->codec->extradata)
         return AVERROR(ENOMEM);
     st->codec->extradata[0] = 16;