CVE-2021-40055Network attack vector

Update integrity loss via recovery-mode interception

Published Mar 7, 2022 · Updated Aug 4, 2024

Man-in-the-middle flaws in recovery-mode updates for Huawei EMUI and HarmonyOS allow attackers to alter downloaded system updates. Huawei identifies the affected locus as the recovery-mode update download but has not disclosed the failed authenticity check or other validation error. Exploitation requires a man-in-the-middle position during the download, and the documented consequence is loss of update integrity.

CVSS severity5.9
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Man-in-the-middle flaws in recovery-mode updates for Huawei EMUI and HarmonyOS allow attackers to alter downloaded system updates. Huawei identifies the affected locus as the recovery-mode update download but has not disclosed the failed authenticity check or other validation error. Exploitation requires a man-in-the-middle position during the download, and the documented consequence is loss of update integrity.

The record

CVE
CVE-2021-40055
Published
Mar 7, 2022
Updated
Aug 4, 2024
Vendor
Huawei Technologies Co., Ltd.
Product
HarmonyOS
Classifications
T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 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
MindSpore · EMUIversion=10.0.0; version=10.1.0; version=10.1.1; version=11.0.0; version=11.0.1; version=12.0.0

Published CVSS scores

7.1NIST NVDAV:N/AC:M/Au:N/C:N/I:C/A:N
5.9NIST NVDCVSS:3.1/AV:N/AC:H/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.

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

T1557Adversary-in-the-Middle

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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