HOMEVULNERABILITIESCVE-2021-3537
MEDIUM

CVE-2021-3537

CWE-476Published: May 14, 2021· Updated: Jun 17, 2026

5.9
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-3537 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.9.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
netapp8 product(s)
active iq unified managerclustered data ontapclustered data ontap antivirus connectormanageability software development kitontap select deploy administration utilitysnapdrivehci h410c firmwarehci h410c
Oracle7 product(s)
communications cloud native core network function cloud native environmententerprise manager base platformenterprise manager ops centermysql workbenchopenjdkpeoplesoft enterprise peopletoolsreal user experience insight
Red Hat2 product(s)
jboss core servicesenterprise linux
xmlsoft1 product(s)
libxml2
Source: NVD CPE · 25 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1956522
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpuoct2021.html
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1956522
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpuoct2021.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/05/msg00008.html
ADVISORYhttps://security.gentoo.org/glsa/202107-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20210625-0002/
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/05/msg00008.html
ADVISORYhttps://security.gentoo.org/glsa/202107-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20210625-0002/

All References (18)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1956522Issue Tracking · Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/05/msg00008.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6YIZAFDGX6/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4GY3NIV52WV/
→
https://security.gentoo.org/glsa/202107-05Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210625-0002/Third Party Advisory
→
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch · Third Party Advisory
→
https://www.oracle.com/security-alerts/cpujul2022.htmlNot Applicable
→
https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1956522Issue Tracking · Patch · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/05/msg00008.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6YIZAFDGX6/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4GY3NIV52WV/
→
https://security.gentoo.org/glsa/202107-05Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210625-0002/Third Party Advisory

Quick Facts

CVE IDCVE-2021-3537
CVSS Score5.9 / 10
SeverityMEDIUM
WeaknessCWE-476
CISA KEVNo
Affected6 vendor(s)
PublishedMay 14, 2021

Related CVEs (CWE-476)

CVE-2010-2495
10.0
CVE-2022-36648
10.0
CVE-2022-26096
9.8
CVE-2016-10344
9.8
CVE-2022-26093
9.8
CVE-2022-26095
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3537 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2021-3537·NVD