CVE-2021-3541

libxml2: Exponential entity expansion attack bypasses all existing protection mechanisms

Severity Score

6.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A flaw was found in libxml2. Exponential entity expansion attack its possible bypassing all existing protection mechanisms and leading to denial of service.

Se ha encontrado un fallo en libxml2. Es posible un ataque de expansión exponencial de entidades omitiendo todos los mecanismos de protección existentes y conllevando a una denegación de servicio

Red Hat JBoss Core Services is a set of supplementary software for Red Hat JBoss middleware products. This software, such as Apache HTTP Server, is common to multiple JBoss middleware products, and is packaged under Red Hat JBoss Core Services to allow for faster distribution of updates, and for a more consistent update experience. This release adds the new Apache HTTP Server 2.4.37 Service Pack 11 packages that are part of the JBoss Core Services offering. This release serves as a replacement for Red Hat JBoss Core Services Apache HTTP Server 2.4.37 Service Pack 10 and includes bug fixes and enhancements. Issues addressed include HTTP request smuggling, buffer overflow, bypass, null pointer, and use-after-free vulnerabilities.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

Single

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-05-10 CVE Reserved
2021-06-17 CVE Published
2024-08-03 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-400: Uncontrolled Resource Consumption
CWE-776: Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

CAPEC

References (4)

URL	Tag	Source
https://security.netapp.com/advisory/ntap-20210805-0007	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://bugzilla.redhat.com/show_bug.cgi?id=1950515	2022-03-01
https://www.oracle.com/security-alerts/cpujan2022.html	2022-03-01

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2021-3541	2022-04-20

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Netapp Search vendor "Netapp"	H410c Firmware Search vendor "Netapp" for product "H410c Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H410c Search vendor "Netapp" for product "H410c"	-	-	Safe
Netapp Search vendor "Netapp"	H300s Firmware Search vendor "Netapp" for product "H300s Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H300s Search vendor "Netapp" for product "H300s"	-	-	Safe
Netapp Search vendor "Netapp"	H500s Firmware Search vendor "Netapp" for product "H500s Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H500s Search vendor "Netapp" for product "H500s"	-	-	Safe
Netapp Search vendor "Netapp"	H700s Firmware Search vendor "Netapp" for product "H700s Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H700s Search vendor "Netapp" for product "H700s"	-	-	Safe
Netapp Search vendor "Netapp"	H300e Firmware Search vendor "Netapp" for product "H300e Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H300e Search vendor "Netapp" for product "H300e"	-	-	Safe
Netapp Search vendor "Netapp"	H500e Firmware Search vendor "Netapp" for product "H500e Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H500e Search vendor "Netapp" for product "H500e"	-	-	Safe
Netapp Search vendor "Netapp"	H700e Firmware Search vendor "Netapp" for product "H700e Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H700e Search vendor "Netapp" for product "H700e"	-	-	Safe
Netapp Search vendor "Netapp"	H410s Firmware Search vendor "Netapp" for product "H410s Firmware"	-	-	Affected	in	Netapp Search vendor "Netapp"	H410s Search vendor "Netapp" for product "H410s"	-	-	Safe
Xmlsoft Search vendor "Xmlsoft"		Libxml2 Search vendor "Xmlsoft" for product "Libxml2"				< 2.9.11 Search vendor "Xmlsoft" for product "Libxml2" and version " < 2.9.11"		-		Affected
Redhat Search vendor "Redhat"		Jboss Core Services Search vendor "Redhat" for product "Jboss Core Services"				-		-		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
Netapp Search vendor "Netapp"		Active Iq Unified Manager Search vendor "Netapp" for product "Active Iq Unified Manager"				-		vmware_vsphere		Affected
Netapp Search vendor "Netapp"		Cloud Backup Search vendor "Netapp" for product "Cloud Backup"				-		-		Affected
Netapp Search vendor "Netapp"		Clustered Data Ontap Search vendor "Netapp" for product "Clustered Data Ontap"				-		-		Affected
Netapp Search vendor "Netapp"		Clustered Data Ontap Antivirus Connector Search vendor "Netapp" for product "Clustered Data Ontap Antivirus Connector"				-		-		Affected
Netapp Search vendor "Netapp"		Manageability Software Development Kit Search vendor "Netapp" for product "Manageability Software Development Kit"				-		-		Affected
Netapp Search vendor "Netapp"		Ontap Select Deploy Administration Utility Search vendor "Netapp" for product "Ontap Select Deploy Administration Utility"				-		-		Affected
Netapp Search vendor "Netapp"		Smi-s Provider Search vendor "Netapp" for product "Smi-s Provider"				-		-		Affected
Netapp Search vendor "Netapp"		Snapdrive Search vendor "Netapp" for product "Snapdrive"				-		unix		Affected