CVE-2020-27783

python-lxml: mXSS due to the use of improper parser

Severity Score

6.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A XSS vulnerability was discovered in python-lxml's clean module. The module's parser didn't properly imitate browsers, which caused different behaviors between the sanitizer and the user's page. A remote attacker could exploit this flaw to run arbitrary HTML/JS code.

Se detectó una vulnerabilidad de tipo XSS en el módulo de limpieza de python-lxml. El analizador del módulo no imitaba apropiadamente los navegadores, lo que causaba comportamientos diferentes entre el sanitizador y la página del usuario. Un atacante remoto podría explotar este fallo para ejecutar código HTML/JS arbitrario

A Cross-site Scripting (XSS) vulnerability was found in the python-lxml's clean module. The module's parser did not properly imitate browsers, causing different behaviors between the sanitizer and the user's page. This flaw allows a remote attacker to run arbitrary HTML/JS code. The highest threat from this vulnerability is to confidentiality and integrity.

Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems. Issues addressed include buffer overflow, code execution, cross site scripting, denial of service, information leakage, integer overflow, and traversal vulnerabilities.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-10-27 CVE Reserved
2020-12-03 CVE Published
2024-08-04 CVE Updated
2024-08-04 First Exploit
2025-05-18 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CAPEC

References (9)

URL	Tag	Source
https://lists.debian.org/debian-lts-announce/2020/12/msg00028.html	Mailing List
https://security.netapp.com/advisory/ntap-20210521-0003	Third Party Advisory

URL	Date	SRC
https://advisory.checkmarx.net/advisory/CX-2020-4286	2024-08-04
https://bugzilla.redhat.com/show_bug.cgi?id=1901633	2024-08-04

URL	Date	SRC
https://www.oracle.com//security-alerts/cpujul2021.html	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKG67GPGTV23KADT4D4GK4RMHSO4CIQL	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TMHVKRUT22LVWNL3TB7HPSDHJT74Q3JK	2023-11-07
https://www.debian.org/security/2020/dsa-4810	2023-11-07
https://access.redhat.com/security/cve/CVE-2020-27783	2021-08-24

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Lxml Search vendor "Lxml"		Lxml Search vendor "Lxml" for product "Lxml"				>= 1.2 < 4.6.2 Search vendor "Lxml" for product "Lxml" and version " >= 1.2 < 4.6.2"		-		Affected
Redhat Search vendor "Redhat"		Software Collections Search vendor "Redhat" for product "Software Collections"				-		-		Affected
Redhat Search vendor "Redhat"		Enterprise Linux Search vendor "Redhat" for product "Enterprise Linux"				8.0 Search vendor "Redhat" for product "Enterprise Linux" and version "8.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected
Netapp Search vendor "Netapp"		Snapcenter Search vendor "Netapp" for product "Snapcenter"				-		-		Affected
Oracle Search vendor "Oracle"		Communications Offline Mediation Controller Search vendor "Oracle" for product "Communications Offline Mediation Controller"				12.0.0.3.0 Search vendor "Oracle" for product "Communications Offline Mediation Controller" and version "12.0.0.3.0"		-		Affected
Oracle Search vendor "Oracle"		Zfs Storage Appliance Kit Search vendor "Oracle" for product "Zfs Storage Appliance Kit"				8.8 Search vendor "Oracle" for product "Zfs Storage Appliance Kit" and version "8.8"		-		Affected