diff --git a/libavcodec/lzf.c b/libavcodec/lzf.c
index 35b932bd08..0329fe0eec 100644
--- a/libavcodec/lzf.c
+++ b/libavcodec/lzf.c
@@ -53,6 +53,7 @@ int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size)
                 ret = av_reallocp(buf, *size);
                 if (ret < 0)
                     return ret;
+                p = *buf + len;
             }
 
             bytestream2_get_buffer(gb, p, s);
@@ -75,6 +76,7 @@ int ff_lzf_uncompress(GetByteContext *gb, uint8_t **buf, int64_t *size)
                 ret = av_reallocp(buf, *size);
                 if (ret < 0)
                     return ret;
+                p = *buf + len;
             }
 
             av_memcpy_backptr(p, off, l);