// For flags

CVE-2021-43818

HTML Cleaner allows crafted and SVG embedded scripts to pass through

Severity Score

7.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.

lxml es una biblioteca para procesar XML y HTML en el lenguaje Python. En versiones anteriores a 4.6.5, el limpiador de HTML en lxml.html dejaba pasar determinado contenido de scripts manipulados, así como contenido de scripts en archivos SVG insertados usando URIs de datos. Los usuarios que empleen el limpiador de HTML en un contexto relevante para la seguridad deben actualizar a lxml versión 4.6.5 para recibir un parche. No se presentan soluciones conocidas disponibles

There's a flaw in python-lxml's HTML Cleaner component, which is responsible for sanitizing HTML and Javascript. An attacker who is able to submit a crafted payload to a web service using python-lxml's HTML Cleaner may be able to trigger script execution in clients such as web browsers. This can occur because the HTML Cleaner did not remove scripts within SVG images in data URLs such as <img src="">. XSS can result in impacts to the integrity and availability of the web page, as well as a potential impact to data confidentiality in some circumstances.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
High
Availability
Low
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-11-16 CVE Reserved
  • 2021-12-13 CVE Published
  • 2024-08-04 CVE Updated
  • 2024-10-21 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC
References (16)
URL Date SRC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Netapp
Search vendor "Netapp"
Hci Storage Node Firmware
Search vendor "Netapp" for product "Hci Storage Node Firmware"
--
Affected
in Netapp
Search vendor "Netapp"
Hci Storage Node
Search vendor "Netapp" for product "Hci Storage Node"
--
Safe
Lxml
Search vendor "Lxml"
Lxml
Search vendor "Lxml" for product "Lxml"
< 4.6.5
Search vendor "Lxml" for product "Lxml" and version " < 4.6.5"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
Fedora
Search vendor "Fedoraproject" for product "Fedora"
34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected
Fedoraproject
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Fedora
Search vendor "Fedoraproject" for product "Fedora"
35
Search vendor "Fedoraproject" for product "Fedora" and version "35"
-
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
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Debian Linux
Search vendor "Debian" for product "Debian Linux"
10.0
Search vendor "Debian" for product "Debian Linux" and version "10.0"
-
Affected
Debian
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Debian Linux
Search vendor "Debian" for product "Debian Linux"
11.0
Search vendor "Debian" for product "Debian Linux" and version "11.0"
-
Affected
Netapp
Search vendor "Netapp"
Solidfire
Search vendor "Netapp" for product "Solidfire"
--
Affected
Netapp
Search vendor "Netapp"
Solidfire Enterprise Sds
Search vendor "Netapp" for product "Solidfire Enterprise Sds"
--
Affected
Oracle
Search vendor "Oracle"
Communications Cloud Native Core Binding Support Function
Search vendor "Oracle" for product "Communications Cloud Native Core Binding Support Function"
22.1.3
Search vendor "Oracle" for product "Communications Cloud Native Core Binding Support Function" and version "22.1.3"
-
Affected
Oracle
Search vendor "Oracle"
Communications Cloud Native Core Network Exposure Function
Search vendor "Oracle" for product "Communications Cloud Native Core Network Exposure Function"
22.1.1
Search vendor "Oracle" for product "Communications Cloud Native Core Network Exposure Function" and version "22.1.1"
-
Affected
Oracle
Search vendor "Oracle"
Communications Cloud Native Core Policy
Search vendor "Oracle" for product "Communications Cloud Native Core Policy"
22.2.0
Search vendor "Oracle" for product "Communications Cloud Native Core Policy" and version "22.2.0"
-
Affected
Oracle
Search vendor "Oracle"
Http Server
Search vendor "Oracle" for product "Http Server"
12.2.1.3.0
Search vendor "Oracle" for product "Http Server" and version "12.2.1.3.0"
-
Affected
Oracle
Search vendor "Oracle"
Http Server
Search vendor "Oracle" for product "Http Server"
12.2.1.4.0
Search vendor "Oracle" for product "Http Server" and version "12.2.1.4.0"
-
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