8.2
HIGH
CVE-2021-43818
XMLsec HTML Cleaner Unvalidated Input Vulnerability in lxml
Description

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.

INFO

Published Date :

Dec. 13, 2021, 6:15 p.m.

Last Modified :

Nov. 7, 2023, 3:39 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

4.7

Exploitability Score :

2.8
Affected Products

The following products are affected by CVE-2021-43818 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Oracle zfs_storage_appliance_kit
2 Oracle communications_cloud_native_core_policy
3 Oracle http_server
4 Oracle communications_cloud_native_core_binding_support_function
5 Oracle communications_cloud_native_core_network_exposure_function
1 Netapp solidfire
2 Netapp hci_storage_node_firmware
3 Netapp solidfire_enterprise_sds
1 Fedoraproject fedora
1 Debian debian_linux
1 Lxml lxml
: Total Affected Vendor : 5 | Products : 11
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-43818.

URL Resource
https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a Patch Third Party Advisory
https://github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776 Patch Third Party Advisory
https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0 Patch Third Party Advisory
https://github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8 Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/
https://security.gentoo.org/glsa/202208-06 Third Party Advisory
https://security.netapp.com/advisory/ntap-20220107-0005/ Third Party Advisory
https://www.debian.org/security/2022/dsa-5043 Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Patch Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-43818 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-43818 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/ [No types assigned]
    Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/ [No types assigned]
    Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/ [No types assigned]
    Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/ [No types assigned]
    Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/
    Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/
    Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/
    Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/
  • Modified Analysis by [email protected]

    Dec. 09, 2022

    Action Type Old Value New Value
    Changed Reference Type https://security.gentoo.org/glsa/202208-06 No Types Assigned https://security.gentoo.org/glsa/202208-06 Third Party Advisory
  • CVE Modified by [email protected]

    Aug. 10, 2022

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/202208-06 [No Types Assigned]
  • Modified Analysis by [email protected]

    Aug. 09, 2022

    Action Type Old Value New Value
    Changed Reference Type https://www.oracle.com/security-alerts/cpujul2022.html No Types Assigned https://www.oracle.com/security-alerts/cpujul2022.html Patch, Third Party Advisory
    Changed CPE Configuration OR *cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:* OR *cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:* *cpe:2.3:a:oracle:communications_cloud_native_core_network_exposure_function:22.1.1:*:*:*:*:*:*:* *cpe:2.3:a:oracle:communications_cloud_native_core_policy:22.2.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Jul. 25, 2022

    Action Type Old Value New Value
    Added Reference https://www.oracle.com/security-alerts/cpujul2022.html [No Types Assigned]
  • Modified Analysis by [email protected]

    Jun. 16, 2022

    Action Type Old Value New Value
    Changed Reference Type https://www.oracle.com/security-alerts/cpuapr2022.html No Types Assigned https://www.oracle.com/security-alerts/cpuapr2022.html Patch, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:* *cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Apr. 20, 2022

    Action Type Old Value New Value
    Added Reference https://www.oracle.com/security-alerts/cpuapr2022.html [No Types Assigned]
  • Modified Analysis by [email protected]

    Feb. 10, 2022

    Action Type Old Value New Value
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html Third Party Advisory https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/ Mailing List, Third Party Advisory
    Changed Reference Type https://security.netapp.com/advisory/ntap-20220107-0005/ No Types Assigned https://security.netapp.com/advisory/ntap-20220107-0005/ Third Party Advisory
    Changed Reference Type https://www.debian.org/security/2022/dsa-5043 No Types Assigned https://www.debian.org/security/2022/dsa-5043 Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:solidfire_enterprise_sds:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:netapp:hci_storage_node_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:hci_storage_node:-:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Jan. 23, 2022

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/ [No Types Assigned]
  • CVE Modified by [email protected]

    Jan. 15, 2022

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/ [No Types Assigned]
  • CVE Modified by [email protected]

    Jan. 13, 2022

    Action Type Old Value New Value
    Added Reference https://www.debian.org/security/2022/dsa-5043 [No Types Assigned]
  • CVE Modified by [email protected]

    Jan. 10, 2022

    Action Type Old Value New Value
    Added Reference https://security.netapp.com/advisory/ntap-20220107-0005/ [No Types Assigned]
  • Modified Analysis by [email protected]

    Jan. 04, 2022

    Action Type Old Value New Value
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html No Types Assigned https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/ Mailing List, Third Party Advisory
    Added CWE NIST CWE-79
    Changed CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* OR *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Dec. 30, 2021

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html [No Types Assigned]
  • CVE Modified by [email protected]

    Dec. 26, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/ [No Types Assigned]
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/ [No Types Assigned]
  • Initial Analysis by [email protected]

    Dec. 16, 2021

    Action Type Old Value New Value
    Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism
    Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:P/I:P/A:P)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
    Changed Reference Type https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a No Types Assigned https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a Patch, Third Party Advisory
    Changed Reference Type https://github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776 No Types Assigned https://github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776 Patch, Third Party Advisory
    Changed Reference Type https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0 No Types Assigned https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0 Patch, Third Party Advisory
    Changed Reference Type https://github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8 No Types Assigned https://github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8 Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:lxml:lxml:*:*:*:*:*:*:*:* versions up to (excluding) 4.6.5
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* *cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-43818 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-43818 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-6: Argument Injection Argument Injection CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-34: HTTP Response Splitting HTTP Response Splitting CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-83: XPath Injection XPath Injection CAPEC-84: XQuery Injection XQuery Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-105: HTTP Request Splitting HTTP Request Splitting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-250: XML Injection XML Injection CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-273: HTTP Response Smuggling HTTP Response Smuggling CAPEC-63: Cross-Site Scripting (XSS) Cross-Site Scripting (XSS) CAPEC-85: AJAX Footprinting AJAX Footprinting CAPEC-209: XSS Using MIME Type Mismatch XSS Using MIME Type Mismatch CAPEC-588: DOM-Based XSS DOM-Based XSS CAPEC-591: Reflected XSS Reflected XSS CAPEC-592: Stored XSS Stored XSS
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.96 }} 0.28%

score

0.83661

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: