---
id: CVE-2021-3541
title: A flaw was found in libxml2
summary: >-
  A flaw was found in libxml2. Exponential entity expansion attack its possible
  bypassing all existing protection mechanisms and leading to denial of service.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-776
vendor: xmlsoft
product: libxml2
affected:
  - libxml2 < 2.9.11
  - jboss_core_services
  - zfs_storage_appliance_kit = 8.8
  - active_iq_unified_manager
  - cloud_backup
  - clustered_data_ontap
  - clustered_data_ontap_antivirus_connector
  - manageability_software_development_kit
  - ontap_select_deploy_administration_utility
  - smi-s_provider
  - snapdrive
  - h410c_firmware
  - h300s_firmware
  - h500s_firmware
  - h700s_firmware
  - h300e_firmware
  - h500e_firmware
  - h700e_firmware
  - h410s_firmware
patched:
  - libxml2 2.9.11
published: '2021-07-09'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T10:17:45.397'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-3541'
references:
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1950515'
    label: secalert@redhat.com
  - url: 'https://security.netapp.com/advisory/ntap-20210805-0007/'
    label: secalert@redhat.com
  - url: 'https://www.oracle.com/security-alerts/cpujan2022.html'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1950515'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20210805-0007/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.oracle.com/security-alerts/cpujan2022.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.01964
epssPercentile: 0.79842
ingestedAt: '2026-10-14T10:25:41.191Z'
---

## Overview

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

## Affected

- `libxml2 < 2.9.11`
- `jboss_core_services`
- `zfs_storage_appliance_kit = 8.8`
- `active_iq_unified_manager`
- `cloud_backup`
- `clustered_data_ontap`
- `clustered_data_ontap_antivirus_connector`
- `manageability_software_development_kit`
- `ontap_select_deploy_administration_utility`
- `smi-s_provider`
- `snapdrive`
- `h410c_firmware`
- `h300s_firmware`
- `h500s_firmware`
- `h700s_firmware`
- `h300e_firmware`
- `h500e_firmware`
- `h700e_firmware`
- `h410s_firmware`

## Remediation

Upgrade past the affected range:

- `libxml2 2.9.11`