<s>
In	O
computer	O
security	O
and	O
programming	B-General_Concept
,	O
a	O
buffer	B-General_Concept
over-read	I-General_Concept
is	O
an	O
anomaly	B-Error_Name
where	O
a	O
program	B-Application
,	O
while	O
reading	O
data	O
from	O
a	O
buffer	B-General_Concept
,	O
overruns	O
the	O
buffer	B-General_Concept
's	O
boundary	O
and	O
reads	O
(	O
or	O
tries	O
to	O
read	O
)	O
adjacent	O
memory	B-Architecture
.	O
</s>
<s>
This	O
is	O
a	O
special	O
case	O
of	O
violation	O
of	O
memory	B-Application
safety	I-Application
.	O
</s>
<s>
Buffer	B-General_Concept
over-reads	I-General_Concept
can	O
be	O
triggered	O
,	O
as	O
in	O
the	O
Heartbleed	B-Error_Name
bug	I-Error_Name
,	O
by	O
maliciously	O
crafted	O
inputs	O
that	O
are	O
designed	O
to	O
exploit	O
a	O
lack	O
of	O
bounds	B-Data_Structure
checking	I-Data_Structure
to	O
read	O
parts	O
of	O
memory	B-Architecture
not	O
intended	O
to	O
be	O
accessible	O
.	O
</s>
<s>
They	O
may	O
also	O
be	O
caused	O
by	O
programming	B-Error_Name
errors	I-Error_Name
alone	O
.	O
</s>
<s>
Buffer	B-General_Concept
over-reads	I-General_Concept
can	O
result	O
in	O
erratic	O
program	B-Application
behavior	O
,	O
including	O
memory	B-Architecture
access	O
errors	O
,	O
incorrect	O
results	O
,	O
a	O
crash	B-General_Concept
,	O
or	O
a	O
breach	O
of	O
system	O
security	O
.	O
</s>
<s>
Programming	B-General_Concept
languages	O
commonly	O
associated	O
with	O
buffer	B-General_Concept
over-reads	I-General_Concept
include	O
C	B-Language
and	O
C++	B-Language
,	O
which	O
provide	O
no	O
built-in	O
protection	O
against	O
using	O
pointers	O
to	O
access	O
data	O
in	O
any	O
part	O
of	O
virtual	B-Architecture
memory	I-Architecture
,	O
and	O
which	O
do	O
not	O
automatically	O
check	O
that	O
reading	O
data	O
from	O
a	O
block	O
of	O
memory	B-Architecture
is	O
safe	O
;	O
respective	O
examples	O
are	O
attempting	O
to	O
read	O
more	O
elements	O
than	O
contained	O
in	O
an	O
array	O
,	O
or	O
failing	O
to	O
append	O
a	O
trailing	O
terminator	O
to	O
a	O
null-terminated	B-Data_Structure
string	I-Data_Structure
.	O
</s>
<s>
Bounds	B-Data_Structure
checking	I-Data_Structure
can	O
prevent	O
buffer	B-General_Concept
over-reads	I-General_Concept
,	O
while	O
fuzz	O
testing	O
can	O
help	O
detect	O
them	O
.	O
</s>
