CVE-2021-3520

Publication date 30 April 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
lz4	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Fixed 1.9.3-1ubuntu0.1
	20.10 groovy	Fixed 1.9.2-2ubuntu0.20.10.1
	20.04 LTS focal	Fixed 1.9.2-2ubuntu0.20.04.1
	18.04 LTS bionic	Fixed 0.0~r131-2ubuntu3.1
	16.04 LTS xenial	Fixed 0.0~r131-2ubuntu2+esm1
	14.04 LTS trusty	Fixed 0.0~r114-2ubuntu1+esm2

Get expanded security coverage with Ubuntu Pro

Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.

Get Ubuntu Pro 30-day free trial

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
lz4	Upstream: 8301a21

Severity score breakdown

Parameter	Value
Base score	9.8 · Critical
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H