CVE-2021-3520

Description

There's a flaw in lz4. An attacker who submits a crafted file to an application linked with lz4 may be able to trigger an integer overflow, leading to calling of memmove() on a negative size argument, causing an out-of-bounds write and/or a crash. The greatest impact of this flaw is to availability, with some potential impact to confidentiality and integrity as well.

How to fix CVE-2021-3520

To remediate CVE-2021-3520, upgrade the affected package to a fixed version below.

—upgrade to 1.9.2-r1 or later
—upgrade to 1.9.4 or later
—upgrade to 1.9.3-2 or later
—upgrade to 0.0~r131-2+deb9u1 or later
—upgrade to 1.8.3-1+deb10u1 or later

Is CVE-2021-3520 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (5)

from 0, < 1.9.2-r1
>= 0.0.0-0, < 1.9.4
from 0, < 1.9.3-2
from 0, < 0.0~r131-2+deb9u1
from 0, < 1.8.3-1+deb10u1

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	CRITICAL9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H