CVE-2020-28918Network attack vector

Username enumeration via divergent login responses

Published Feb 16, 2021 · Updated May 30, 2025

Username enumeration in Deepnet Security DualShield 5.9.8.0821 allows remote attackers to identify valid accounts through its login form. The form advances valid names to a password prompt but returns an unknown-username error for invalid names, exposing an account-existence oracle. No authentication or user interaction is required, and the disclosed account validity can support targeted password attacks.

CVSS severity5.3
Medium
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Username enumeration in Deepnet Security DualShield 5.9.8.0821 allows remote attackers to identify valid accounts through its login form. The form advances valid names to a password prompt but returns an unknown-username error for invalid names, exposing an account-existence oracle. No authentication or user interaction is required, and the disclosed account validity can support targeted password attacks.

The record

CVE
CVE-2020-28918
Published
Feb 16, 2021
Updated
May 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1589
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 16, 2021CVE publishedPublication date reported by the CVE source.
  2. May 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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.

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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

T1589Gather Victim Identity Information

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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