CVE-2016-9909

Publication date 22 February 2017

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

The serializer in html5lib before 0.99999999 might allow remote attackers to conduct cross-site scripting (XSS) attacks by leveraging mishandling of the < (less than) character in attribute values.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
html5lib	26.04 LTS resolute	Not affected
	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Not affected
	19.04 disco	Not affected
	18.10 cosmic	Not affected
	18.04 LTS bionic	Not affected
	17.10 artful	Not affected
	17.04 zesty	Not affected
	16.10 yakkety	Ignored end of life
	16.04 LTS xenial	Vulnerable
	14.04 LTS trusty	Not in release
	12.04 LTS precise	Ignored end of life

Notes

sbeattie

same commit as CVE-2016-9910 fix changes externally visible api from True|False boolean to a ternary value, which will break users.

Patch details

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

Package	Patch details
html5lib	Other: 9b8d8eb

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.1 · Medium

Base metrics

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

Scores

Parameter	Value
Base score	6.1 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N