diff --git a/doc/zzuf.1 b/doc/zzuf.1
index ca6963a..4903427 100644
--- a/doc/zzuf.1
+++ b/doc/zzuf.1
@@ -242,6 +242,8 @@ different operating systems and with different target programs is only
 guaranteed when the same version of \fBzzuf\fR is being used.
 .SH BUGS
 .PP
+\fBZzuf\fR probably does not behave correctly with 64-bit offsets.
+.PP
 It is not yet possible to insert or drop bytes from the input, to fuzz
 according to the file format, to swap bytes, etc. More advanced fuzzing
 methods are planned.