CVE-2021-45918Network attack vector

Unauthenticated service termination via unchecked input length

Published Jun 20, 2022 · Updated Sep 17, 2024

Heap-based buffer overflow in National Health Insurance Administration NHI Health Insurance Web Service Component allows remote attackers to terminate service. A component function fails to validate input string length before copying into a reserved heap buffer, allowing a crafted request to overrun memory. No authentication is required, and successful exploitation interrupts the service until a system restart; confidentiality and integrity impacts are not reported.

CVSS severity7.5
High
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in National Health Insurance Administration NHI Health Insurance Web Service Component allows remote attackers to terminate service. A component function fails to validate input string length before copying into a reserved heap buffer, allowing a crafted request to overrun memory. No authentication is required, and successful exploitation interrupts the service until a system restart; confidentiality and integrity impacts are not reported.

The record

CVE
CVE-2021-45918
Published
Jun 20, 2022
Updated
Sep 17, 2024
Vendor
National Health Insurance Administration
Product
NHI Health Insurance Web Service Component
Classifications
CWE-122, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 20, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=42fcc36541e716e23de77d5f325b186a
  2. Affected versionversion=515BE7DE5BCE446177FEE8A6E0665093
  3. Affected versionversion=52EACB7CA2B4D0A5A869DF01079BF4D6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

National Health Insurance Administration · NHI Health Insurance Web Service Componentversion=42fcc36541e716e23de77d5f325b186a; version=515BE7DE5BCE446177FEE8A6E0665093; version=52EACB7CA2B4D0A5A869DF01079BF4D6

Published CVSS scores

7.5TWCERT/CCCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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