diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 8e3a98a7d9..55313525c0 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -1915,7 +1915,7 @@ int ff_mjpeg_find_marker(MJpegDecodeContext *s,
         while (b < t) {
             uint8_t x = src[b++];
             put_bits(&pb, 8, x);
-            if (x == 0xFF) {
+            if (x == 0xFF && b < t) {
                 x = src[b++];
                 if (x & 0x80) {
                     av_log(s->avctx, AV_LOG_WARNING, "Invalid escape sequence\n");