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Vulnerabilities/CVE-2021-43396Public Intelligence Dossier
Source: gnu · Limited verification•Last verified: •Collection Degraded
CVE-2021-43396Unknown / EvaluatingHIGH (raw)CVSS 7.5NVD-CWE-noinfo

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset

Published: 05 Nov 2021•Last updated: 14 Oct 2026, 05:47 PM IST•Source identifier: cve@mitre.org
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
7.5HIGH (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Metric sourcenvd@nist.gov
EPSS probability
3.3%0.033
Percentile88th
Weakness type
NVD-CWE-noinfo
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset. This may affect data integrity in certain iconv() use cases. NOTE: the vendor states "the bug cannot be invoked through user input and requires iconv to be invoked with a NULL inbuf, which ought to require a separate application bug to do so unintentionally. Hence there's no security impact to the bug.

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

7 source-backed products
Affected products and versions (source)
  • gnu glibc · 2.34 · NVD CPE · Source
  • oracle communications cloud native core binding support function · 22.1.3 · NVD CPE · Source
  • oracle communications cloud native core network function cloud native environment · 22.1.0 · NVD CPE · Source
  • oracle communications cloud native core network repository function · 22.1.2; 22.2.0 · NVD CPE · Source
  • oracle communications cloud native core security edge protection proxy · 22.1.1 · NVD CPE · Source
  • oracle communications cloud native core unified data repository · 22.2.0 · NVD CPE · Source
  • oracle enterprise operations monitor · 4.3; 4.4; 5.0 · 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.

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
cve@mitre.org
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:gnu:glibc:2.34:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:22.1.3:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:22.1.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.1.2:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:22.2.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_security_edge_protection_proxy:22.1.1:*:*:*:*:*:*:*, cpe:2.3:a:oracle:communications_cloud_native_core_unified_data_repository:22.2.0:*:*:*:*:*:*:*, cpe:2.3:a:oracle:enterprise_operations_monitor:4.3:*:*:*:*:*:*:*, cpe:2.3:a:oracle:enterprise_operations_monitor:4.4:*:*:*:*:*:*:*, cpe:2.3:a:oracle:enterprise_operations_monitor:5.0:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
oracle.comSource recordnvd.nist.govSource recordblog.tuxcare.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-2021-43396
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2021-43396
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2021-43396"| 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.