CVE-2021-39968Network attack vector

Remote service interruption through undisclosed blocklist flaw

Published Jan 3, 2022 · Updated Aug 4, 2024

Business logic error in Huawei HarmonyOS 2.0 Changlian Blocklist allows remote attackers to interrupt message-class availability. Huawei has not published the faulty operation, input, or code locus within the blocklist logic. Network access without authentication or user interaction is sufficient, but public records do not identify whether exploitation causes a hang, crash, reboot, or another service interruption.

CVSS severity7.5
High
EPSS probability0.66%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Business logic error in Huawei HarmonyOS 2.0 Changlian Blocklist allows remote attackers to interrupt message-class availability. Huawei has not published the faulty operation, input, or code locus within the blocklist logic. Network access without authentication or user interaction is sufficient, but public records do not identify whether exploitation causes a hang, crash, reboot, or another service interruption.

The record

CVE
CVE-2021-39968
Published
Jan 3, 2022
Updated
Aug 4, 2024
Vendor
Huawei Technologies Co., Ltd.
Product
HarmonyOS
Classifications
T1642
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Huawei Technologies Co., Ltd. · HarmonyOSversion=2.0

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS: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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1642Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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