CVE-2021-28957

2021-03-2100:00:00

ubuntu.com

6.1 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

AV:N/AC:M/Au:N/C:N/I:P/A:N

0.002 Low

EPSS

Percentile

61.1%

JSON

An XSS vulnerability was discovered in python-lxml’s clean module versions
before 4.6.3. When disabling the safe_attrs_only and forms arguments, the
Cleaner class does not remove the formaction attribute allowing for JS to
bypass the sanitizer. A remote attacker could exploit this flaw to run
arbitrary JS code on users who interact with incorrectly sanitized HTML.
This issue is patched in lxml 4.6.3.

Bugs

<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=985643>

OSVersionArchitecturePackageVersionFilename
ubuntu18.04noarchlxml< 4.2.1-1ubuntu0.4UNKNOWN
ubuntu20.04noarchlxml< 4.5.0-1ubuntu0.3UNKNOWN
ubuntu20.10noarchlxml< 4.5.2-1ubuntu0.4UNKNOWN
ubuntu14.04noarchlxml< 3.3.3-1ubuntu0.2+esm3) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu16.04noarchlxml< 3.5.0-1ubuntu0.4UNKNOWN

OS	Version	Architecture	Package	Version	Filename
ubuntu	18.04	noarch	lxml	< 4.2.1-1ubuntu0.4	UNKNOWN
ubuntu	20.04	noarch	lxml	< 4.5.0-1ubuntu0.3	UNKNOWN
ubuntu	20.10	noarch	lxml	< 4.5.2-1ubuntu0.4	UNKNOWN
ubuntu	14.04	noarch	lxml	< 3.3.3-1ubuntu0.2+esm3) Available with Ubuntu Pro or Ubuntu Pro (Infra-only	UNKNOWN
ubuntu	16.04	noarch	lxml	< 3.5.0-1ubuntu0.4	UNKNOWN