CVE-2025-34254Network attack vector

Unauthenticated account enumeration via distinct login errors

Published Oct 16, 2025 · Updated Oct 16, 2025

Observable response discrepancy in D-Link Nuclias Connect 1.3.1.4 and earlier allows remote attackers to enumerate valid usernames. The Login endpoint returns distinct JSON error.message values for existing and nonexistent usernames instead of a uniform authentication failure. Unauthenticated network access to the web interface is sufficient, and the resulting account list can support credential targeting without exposing passwords.

CVSS severity6.9
Medium
EPSS probability1.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable response discrepancy in D-Link Nuclias Connect 1.3.1.4 and earlier allows remote attackers to enumerate valid usernames. The Login endpoint returns distinct JSON error.message values for existing and nonexistent usernames instead of a uniform authentication failure. Unauthenticated network access to the web interface is sufficient, and the resulting account list can support credential targeting without exposing passwords.

The record

CVE
CVE-2025-34254
Published
Oct 16, 2025
Updated
Oct 16, 2025
Vendor
D-Link
Product
Nuclias Connect
Classifications
CWE-204, CAPEC-575, T1589.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 16, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <1.3.1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · Nuclias Connectversion=* <1.3.1.4

Published CVSS scores

6.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
5.3NIST NVDCVSS: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.

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-204Observable Response Discrepancy
CAPEC-575Account Footprinting
T1589.001Gather Victim Identity Information: Credentials

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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