CVE-2016-20030Public exploitNetwork attack vector

Username disclosure via partial-match login responses

Published Mar 15, 2026 · Updated Mar 15, 2026

User enumeration in ZKTeco ZKBioSecurity 3.0 allows remote attackers to discover valid usernames through the login endpoint. The authLoginAction!login.do handler evaluates partial username values and returns distinguishable application responses for valid accounts. No authentication or user interaction is required; the disclosed consequence is account discovery for follow-on targeting.

CVSS severity9.3
Critical
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

User enumeration in ZKTeco ZKBioSecurity 3.0 allows remote attackers to discover valid usernames through the login endpoint. The authLoginAction!login.do handler evaluates partial username values and returns distinguishable application responses for valid accounts. No authentication or user interaction is required; the disclosed consequence is account discovery for follow-on targeting.

The record

CVE
CVE-2016-20030
Published
Mar 15, 2026
Updated
Mar 15, 2026
Vendor
ZKTeco
Product
ZKBioSecurity
Classifications
CWE-551, T1589
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 15, 2026Record 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=3.0.1.0_R_230

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ZKTeco · ZKBioSecurityversion=3.0.1.0_R_230

Published CVSS scores

9.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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-551Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
T1589Gather Victim Identity Information

Public exploit references

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Technologies

Your stack

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Your stack

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