CVE-2021-22356Network attack vector

Information disclosure via weak message cryptography

Published Nov 23, 2021 · Updated Aug 3, 2024

Weak cryptography in Huawei IPS, NGFW, Secospace USG, and USG9500 firmware allows attackers to disclose inter-device message data. An undisclosed module applies a weak cryptographic algorithm to inter-device messages; Huawei has not published the algorithm, function, or protocol. Exploitation requires the ability to capture traffic between devices, and the reported consequence is information disclosure without data modification or service interruption.

CVSS severity5.9
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak cryptography in Huawei IPS, NGFW, Secospace USG, and USG9500 firmware allows attackers to disclose inter-device message data. An undisclosed module applies a weak cryptographic algorithm to inter-device messages; Huawei has not published the algorithm, function, or protocol. Exploitation requires the ability to capture traffic between devices, and the reported consequence is information disclosure without data modification or service interruption.

The record

CVE
CVE-2021-22356
Published
Nov 23, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327, T1040
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:N
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
5.5HuaweiCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:F/RL:O/RC:C
5.9HuaweiCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1040Network Sniffing

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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