D-Link Nuclias Connect <=1.3.1.4 Username Enumeration via JSON Login Response
CVE-2025-34254 Published on October 16, 2025
D-Link Nuclias Connect <= v1.3.1.4 Login Account Enumeration
D-Link Nuclias Connect firmware versions <= 1.3.1.4 contain an observable response discrepancy vulnerability. The application's 'Login' endpoint returns distinct JSON responses depending on whether the supplied username is associated with an existing account. Because the responses differ in the `error.message`string value, an unauthenticated remote attacker can enumerate valid usernames/accounts on the server. NOTE: D-Link states that a fix is under development.
Weakness Type
Observable Response Discrepancy
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere. This issue frequently occurs during authentication, where a difference in failed-login messages could allow an attacker to determine if the username is valid or not. These exposures can be inadvertent (bug) or intentional (design).
Products Associated with CVE-2025-34254
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Affected Versions
D-Link Nuclias Connect:- Version * and below 1.3.1.4 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.