CVE-2021-20220

Publication date 23 February 2021

Last updated 11 July 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in Undertow. A regression in the fix for CVE-2020-10687 was found. HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid characters in an HTTP request. This flaw allows an attacker to poison a web-cache, perform an XSS attack, or obtain sensitive information from request other than their own. The highest threat from this vulnerability is to data confidentiality and integrity.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
undertow	26.04 LTS resolute	Needs evaluation
	25.10 questing	Needs evaluation
	25.04 plucky	Ignored end of life, was needs-triage
	24.10 oracular	Ignored end of life, was needs-triage
	24.04 LTS noble	Needs evaluation
	23.10 mantic	Not in release
	23.04 lunar	Not in release
	22.10 kinetic	Ignored end of life, was needs-triage
	22.04 LTS jammy	Needs evaluation
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Ignored end of standard support, was needs-triage
	14.04 LTS trusty	Not in release

Notes

sbeattie

CVE for incomplete fix for CVE-2020-10687, after 2.0.30.SP4

Severity score breakdown

CVSS version: CVSS v3.0

Base score 4.8 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	Low
Integrity impact	Low
Availability impact	None

Scores

Parameter	Value
Base score	4.8 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N