Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-3537

22
FAUCET Score

CVE-2021-3537 is a NULL dereference vulnerability in libxml2 versions prior to 2.9.11, affecting products from vendors like Debian, Oracle, and Red Hat. This flaw occurs when parsing untrusted XML mixed content in recovery mode with post-validation, leading to application crashes. Rated Medium (CVSS 5.9), it requires high attack complexity and impacts system availability. There is no evidence of active exploitation, public exploit code, or Metasploit/Nuclei modules, though it has garnered some community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.9.11CPE matchmatch criteria
cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:redhat:jboss_core_services:-:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.9MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.50%
Probability of exploitation in next 30 days
EPSS Percentile
88.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0350 is in the 83rd percentile among its peer group of 19,958 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (45)

elasticpatch availablevia llm_extracted
Fixed in: ['8.1.13', '8.2.10', '9.0.4', '9.0.2209.3']
microsoftpatch availablevia msrc
Product: 19055-16820Fixed in: 2.9.12-1
microsoftpatch availablevia msrc
Product: cm1 libxml2 2.9.12-1 on CBL Mariner 1.0Fixed in: 2.9.12-1
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-httpd-0:2.4.37-80.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-mod_cluster-native-0:1.3.16-10.Final_redhat_2.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-mod_http2-0:1.15.7-22.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-mod_jk-0:1.2.48-29.redhat_1.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-mod_md-1:2.0.8-41.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-mod_security-0:2.9.2-68.GA.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-nghttp2-0:1.39.2-41.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-openssl-1:1.1.1g-11.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-openssl-chil-0:1.0.0-11.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-openssl-pkcs11-0:0.4.10-26.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-apr-util-0:1.6.1-91.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-curl-0:7.78.0-3.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-httpd-0:2.4.37-80.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-mod_cluster-native-0:1.3.16-10.Final_redhat_2.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-mod_http2-0:1.15.7-22.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-mod_jk-0:1.2.48-29.redhat_1.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-mod_md-1:2.0.8-41.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-mod_security-0:2.9.2-68.GA.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-nghttp2-0:1.39.2-41.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-openssl-1:1.1.1g-11.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-openssl-chil-0:1.0.0-11.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-openssl-pkcs11-0:0.4.10-26.jbcs.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: libxml2-0:2.9.7-9.el8_4.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-controller-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-log-reader-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-must-gather-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-operator-bundle:v1.4.6-5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-registry-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-rsync-transfer-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-ui-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-velero-plugin-for-aws-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-velero-plugin-for-gcp-rhel8:v1.4.6-3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-velero-plugin-for-microsoft-azure-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-velero-rhel8:v1.4.6-5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-velero-plugin-rhel8:v1.4.6-4
View patch
redhatpatch availablevia redhat_api
Product: Text-Only JBCSFixed in: libxml2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Migration Toolkit for Containers 1.4Fixed in: rhmtc/openshift-migration-velero-restic-restore-helper-rhel8:v1.4.6-5
View patch
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-apr-util-0:1.6.1-91.el8jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-curl-0:7.78.0-3.el8jbcs
View patch
rubygemspatch availablevia ghsa
Product: nokogiriFixed in: 1.11.4

Vendor Advisories (4)

elasticllm-elastic-1862d04bb8fb6af4HIGH

February Third Party Package Updates in Splunk Enterprise

Feb 14, 2023
rubygemsGHSA-286v-pcf5-25rcmedium

Nokogiri Implements libxml2 version vulnerable to null pointer dereferencing

May 24, 2022
microsoft2021-May/CVE-2021-3537Moderate

A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

May 11, 2021
redhatCVE-2021-3537Moderate

libxml2: NULL pointer dereference when post-validating mixed content parsed in recovery mode

May 1, 2021

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
lists.debian.org / debian-lts-announce/2021/05/msg00008.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6YIZAFDGX6
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4GY3NIV52WV
security.gentoo.org / glsa/202107-05
Third Party Advisory
security.netapp.com / advisory/ntap-20210625-0002
Third Party Advisory
oracle.com / security-alerts/cpuapr2022.html
PatchThird Party Advisory
oracle.com / security-alerts/cpujul2022.html
Not Applicable
oracle.com / security-alerts/cpuoct2021.html
PatchThird Party Advisory