diff -urp firefox-52.6.0esr.orig/media/libtheora/lib/huffdec.c firefox-52.6.0esr/media/libtheora/lib/huffdec.c
--- firefox-52.6.0esr.orig/media/libtheora/lib/huffdec.c	2017-04-10 21:13:12.000000000 -0500
+++ firefox-52.6.0esr/media/libtheora/lib/huffdec.c	2025-04-10 12:49:48.926330652 -0500
@@ -225,6 +225,7 @@ int oc_huff_tree_unpack(oc_pack_buf *_op
         _tokens[ntokens][1]=(unsigned char)(len+neb);
         ntokens++;
       }
+      if(len<=0)break;
       code_bit=0x80000000U>>len-1;
       while(len>0&&(code&code_bit)){
         code^=code_bit;