diff --git a/libavcodec/kmvc.c b/libavcodec/kmvc.c
index 30939ab..69b5937 100644
--- a/libavcodec/kmvc.c
+++ b/libavcodec/kmvc.c
@@ -33,6 +33,7 @@
 #define KMVC_KEYFRAME 0x80
 #define KMVC_PALETTE  0x40
 #define KMVC_METHOD   0x0F
+#define MAX_PALSIZE   256
 
 /*
  * Decoder context
@@ -43,7 +44,7 @@
 
     int setpal;
     int palsize;
-    uint32_t pal[256];
+    uint32_t pal[MAX_PALSIZE];
     uint8_t *cur, *prev;
     uint8_t *frm0, *frm1;
 } KmvcContext;
@@ -366,6 +367,10 @@
         c->palsize = 127;
     } else {
         c->palsize = AV_RL16(avctx->extradata + 10);
+        if (c->palsize >= MAX_PALSIZE) {
+            av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
+            return AVERROR_INVALIDDATA;
+        }
     }
 
     if (avctx->extradata_size == 1036) {        // palette in extradata