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Vulnerabilities/CVE-2021-3516Public Intelligence Dossier
Source: xmlsoft · Limited verification•Last verified: •Collection Degraded
CVE-2021-3516Unknown / EvaluatingHIGH (raw)CVSS 7.8CWE-416

There's a flaw in libxml2's xmllint in versions before 2.9.11

Published: 01 Jun 2021•Last updated: 14 Oct 2026, 03:47 PM IST•Source identifier: secalert@redhat.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance not available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.8HIGH (raw)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Metric sourcenvd@nist.gov
EPSS probability
2%0.020
Percentile81st
Weakness type
CWE-416
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

There's a flaw in libxml2's xmllint in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by xmllint could trigger a use-after-free. The greatest impact of this flaw is to confidentiality, integrity, and availability.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

9 source-backed products
Affected products and versions (source)
  • xmlsoft xmllint · < 2.9.11 · NVD CPE · Source
  • debian debian linux · 9.0 · NVD CPE · Source
  • fedoraproject fedora · 33; 34 · NVD CPE · Source
  • redhat jboss core services · version range not provided by source · NVD CPE · Source
  • redhat enterprise linux · 6.0; 7.0; 8.0 · 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 ontap select deploy administration utility · version range not provided by source · NVD CPE · Source
  • oracle zfs storage appliance kit · 8.8 · NVD CPE · Source
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.

No rule-based guidance for this vulnerability class

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:xmllint:*:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*, cpe:2.3:a:redhat:jboss_core_services:-:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*, cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*, cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*, cpe:2.3:a:netapp:clustered_data_ontap_antivirus_connector:-:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
gitlab.gnome.orgSource recordnvd.nist.govSource recordbugzilla.redhat.comSource 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-2021-3516
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-3516
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-3516"| 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.