ervik.as
medium · CVSS 5.3Published 9/15/2026 at 10:17 AMCWE-203

The self-registration flow accepts user-supplied input for usernames without adequately preventing the disclosure of username existence. Whe…

The self-registration flow accepts user-supplied input for usernames without adequately preventing the disclosure of username existence. When a user attempts to register with an existing username, the system responds with an error message that explicitly indicates the username is already in use. This behavior allows an attacker to discover valid usernames within the system. The discovery of valid usernames can facilitate subsequent attacks such as brute force, social engineering, and targeted phishing campaigns.

Why it matters

Internet-facing
Not identified as a common internet-facing category
Exploitation likelihood
high
  • Remotely exploitable over the network — no physical or local access required
  • Low attack complexity — no special conditions needed to exploit
  • No authentication required
  • No user interaction needed — can be exploited automatically
Recommended mitigation

Apply the vendor patch as soon as it's available or already released.

This analysis is generated from structured CVSS vector data, CISA KEV cross-referencing, and vendor/product category rules — not a manual expert review. Treat it as a starting point, not a substitute for your own assessment.

CVSS Vector Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack Vector
Network
Complexity
Low
Privileges Req.
None
User Interaction
None

EU Vulnerability Database (ENISA)

EUVD ID
EUVD-2025-210910
View on EUVD

EUVD is ENISA's EU vulnerability database, still in beta. EPSS is a probabilistic exploitation-likelihood score, not a certainty.

View official CVE record

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