diff --git a/libavcodec/jpeglsdec.c b/libavcodec/jpeglsdec.c
index 60bf569a1f..564a93f0cc 100644
--- a/libavcodec/jpeglsdec.c
+++ b/libavcodec/jpeglsdec.c
@@ -207,6 +207,11 @@ static inline void ls_decode_line(JLSState *state, MJpegDecodeContext *s, void *
                 x += stride;
             }
 
+            if (x >= w) {
+                av_log(NULL, AV_LOG_ERROR, "run overflow\n");
+                return;
+            }
+
             /* decode run termination value */
             Rb = R(last, x);
             RItype = (FFABS(Ra - Rb) <= state->near) ? 1 : 0;