CVE-2021-40028Public exploitNetwork attack vector

Data integrity compromise via unchecked TLV offsets

Published Jan 7, 2022 · Updated Aug 4, 2024

Out-of-bounds writes in the eID module in Huawei HarmonyOS 2.0 allow remote attackers to compromise data integrity via crafted input. Encap_tlv_for_hash_zip accepts large hash lengths, then writes TLV type and length fields past the buffer and can underflow a later copy size. Exploitation requires reaching the device's eID trustlet; the demonstrated writes did not crash it, and the documented impact is limited to data integrity.

CVSS severity7.5
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds writes in the eID module in Huawei HarmonyOS 2.0 allow remote attackers to compromise data integrity via crafted input. Encap_tlv_for_hash_zip accepts large hash lengths, then writes TLV type and length fields past the buffer and can underflow a later copy size. Exploitation requires reaching the device's eID trustlet; the demonstrated writes did not crash it, and the documented impact is limited to data integrity.

The record

CVE
CVE-2021-40028
Published
Jan 7, 2022
Updated
Aug 4, 2024
Vendor
Huawei Technologies Co., Ltd.
Product
HarmonyOS
Classifications
CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 7, 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

5.0NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

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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