HOMEVULNERABILITIESCVE-2021-3517
HIGH

CVE-2021-3517

CWE-787Published: May 19, 2021· Updated: Jun 17, 2026

8.6
CVSS v3.1

Official Description

There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker who is able to supply a crafted file to be processed by an application linked with the affected functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to application availability, with some potential impact to confidentiality and integrity if an attacker is able to use memory information to further exploit the application.

NVD Source

Technical Analysis

CVE-2021-3517 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 8.6.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
netapp17 product(s)
active iq unified managerclustered data ontapclustered data ontap antivirus connectore-series santricity os controllere-series santricity storage managere-series santricity web serviceshci management nodemanageability software development kitoncommand insightoncommand workflow automationontap select deploy administration utilitysantricity unified manager+5
Oracle7 product(s)
communications cloud native core network function cloud native environmententerprise manager base platformmysql workbenchopenjdkpeoplesoft enterprise peopletoolsreal user experience insightzfs storage appliance kit
Red Hat2 product(s)
jboss core servicesenterprise linux
xmlsoft1 product(s)
libxml2
Source: NVD CPE · 32 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=1954232
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujan2022.html
PATCHhttps://www.oracle.com/security-alerts/cpuoct2021.html
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1954232
PATCHhttps://www.oracle.com/security-alerts/cpuapr2022.html
PATCHhttps://www.oracle.com/security-alerts/cpujan2022.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://security.netapp.com/advisory/ntap-20211022-0004/
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://security.netapp.com/advisory/ntap-20211022-0004/

All References (26)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1954232Issue Tracking · Patch · Third Party Advisory
→
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
→
https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
→
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://security.netapp.com/advisory/ntap-20211022-0004/Third Party Advisory
→
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch · Third Party Advisory
→
https://www.oracle.com/security-alerts/cpujan2022.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=1954232Issue Tracking · Patch · Third Party Advisory
→
https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E

Quick Facts

CVE IDCVE-2021-3517
CVSS Score8.6 / 10
SeverityHIGH
WeaknessCWE-787
CISA KEVNo
Affected6 vendor(s)
PublishedMay 19, 2021

Related CVEs (CWE-787)

CVE-2026-4746
10.0
CVE-2015-5105
10.0
CVE-2009-2466
10.0
CVE-2026-42369
10.0
CVE-2002-2227
10.0
CVE-2015-5096
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3517 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.
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