CVE-2021-39520

Publication date 20 September 2021

Last updated 26 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

An issue was discovered in libjpeg through 2020021. A NULL pointer dereference exists in the function BlockBitmapRequester::PushReconstructedData() located in blockbitmaprequester.cpp. It allows an attacker to cause Denial of Service.

Read the notes from the security team

Status

Package Ubuntu Release Status

Notes

jdstrand

libjpeg-turbo is a fork of libjpeg8

mdeslaur

file doesn't exist in libjpeg-turbo

eslerm

libjpeg-turbo/libjpeg6b/libjpeg8/libjpeg9 are from different codebases only libjpeg is affected

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H