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Collection Degraded30 / 46 Sources HealthyPublic Intel Only
Vulnerabilities/CVE-2021-3517Public Intelligence Dossier
Source: xmlsoft · Limited verification•Last verified: •Collection Degraded
CVE-2021-3517Unknown / EvaluatingHIGH (raw)CVSS 8.6CWE-787

There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11

Published: 19 May 2021•Last updated: 14 Oct 2026, 03:47 PM IST•Source identifier: secalert@redhat.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
8.6HIGH (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Metric sourcenvd@nist.gov
EPSS probability
17%0.170
Percentile97th
Weakness type
CWE-787
CWE-125
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: Microsoft or Microsoft-managed product relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

28 source-backed products
Affected products and versions (source)
  • xmlsoft libxml2 · < 2.9.11 · NVD CPE · Source
  • redhat jboss core services · version range not provided by source · NVD CPE · Source
  • redhat enterprise linux · 8.0 · NVD CPE · Source
  • fedoraproject fedora · 33; 34 · NVD CPE · Source
  • debian debian linux · 9.0 · NVD CPE · Source
  • netapp active iq unified manager · version range not provided by source · NVD CPE · Source
  • netapp clustered data ontap · version range not provided by source · NVD CPE · Source
  • netapp clustered data ontap antivirus connector · version range not provided by source · NVD CPE · Source
  • netapp e-series santricity os controller · >= 11.0.0 <= 11.70.1 · NVD CPE · Source
  • netapp e-series santricity storage manager · version range not provided by source · NVD CPE · Source
  • netapp e-series santricity web services · version range not provided by source · NVD CPE · Source
  • netapp hci management node · version range not provided by source · NVD CPE · Source
  • netapp manageability software development kit · version range not provided by source · NVD CPE · Source
  • netapp oncommand insight · version range not provided by source · NVD CPE · Source
  • netapp oncommand workflow automation · version range not provided by source · NVD CPE · Source
  • netapp ontap select deploy administration utility · version range not provided by source · NVD CPE · Source
  • netapp santricity unified manager · version range not provided by source · NVD CPE · Source
  • netapp snapdrive · version range not provided by source · NVD CPE · Source
  • netapp snapmanager · version range not provided by source · NVD CPE · Source
  • netapp solidfire · version range not provided by source · NVD CPE · Source
  • netapp hci h410c firmware · version range not provided by source · NVD CPE · Source
  • oracle communications cloud native core network function cloud native environment · 1.10.0 · NVD CPE · Source
  • oracle enterprise manager base platform · 13.4.0.0; 13.5.0.0 · NVD CPE · Source
  • oracle mysql workbench · <= 8.0.26 · NVD CPE · Source
  • oracle openjdk · 8 · NVD CPE · Source
  • oracle peoplesoft enterprise peopletools · 8.58 · NVD CPE · Source
  • oracle real user experience insight · 13.4.1.0; 13.5.1.0 · NVD CPE · Source
  • oracle zfs storage appliance kit · 8.8 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:netapp:hci_h410c:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched network-unauthenticated (CVSS AV:N, CVSS PR:N, CVSS UI:N)

Exposure

  1. Identify devices reporting this CVE and note which expose the affected service to untrusted networks.Telemetry: DeviceTvmSoftwareVulnerabilities · A network-reachable, no-privilege vector makes internet-facing instances the first exposure question. · Rule network-unauthenticated

Exploitation evidence

  1. Review inbound connections to the affected service from unexpected sources since the advisory date.Telemetry: DeviceNetworkEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule network-unauthenticated

Response

  1. Confirm the source-stated update is installed and the CVE is no longer reported.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies remediation. · Rule network-unauthenticated

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
secalert@redhat.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*, cpe:2.3:a:redhat:jboss_core_services:-:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*, cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*, cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:windows:*:*, cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*, cpe:2.3:a:netapp:clustered_data_ontap_antivirus_connector:-:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
bugzilla.redhat.comSource recordnvd.nist.govSource recordlists.apache.orgSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2021-3517
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-3517
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-3517"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.