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Collection Degraded30 / 46 Sources HealthyPublic Intel Only
Vulnerabilities/CVE-2018-20843Public Intelligence Dossier
Source: libexpat project · Limited verification•Last verified: •Collection Degraded
CVE-2018-20843Unknown / EvaluatingHIGH (raw)CVSS 7.8CWE-611

In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).

Published: 24 Jun 2019•Last updated: 14 Oct 2026, 12:46 PM IST•Source identifier: cve@mitre.org
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)
AV:N/AC:L/Au:N/C:N/I:N/A:C
Metric sourcenvd@nist.gov
EPSS probability
7.1%0.071
Percentile94th
Weakness type
CWE-611
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).

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)
  • libexpat project libexpat · < 2.2.7 · NVD CPE · Source
  • canonical ubuntu linux · 12.04; 14.04; 16.04; 18.04; 18.10; 19.04 · NVD CPE · Source
  • debian debian linux · 8.0; 9.0 · NVD CPE · Source
  • fedoraproject fedora · 29; 30 · NVD CPE · Source
  • opensuse leap · 15.0; 15.1 · NVD CPE · Source
  • oracle hospitality res 3700 · >= 5.7 <= 5.7.6 · NVD CPE · Source
  • oracle http server · 12.1.3.0; 12.2.1.4.0 · NVD CPE · Source
  • oracle outside in technology · 8.5.4; 8.5.5 · NVD CPE · Source
  • tenable nessus · < 8.15.0 · 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
cve@mitre.org
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*, cpe:2.3:o:canonical:ubuntu_linux:19.04:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*, cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*, cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
github.comSource recordnvd.nist.govSource recordbugs.chromium.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-2018-20843
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2018-20843
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2018-20843"| 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.