CVE-2026-7167: Email Validation Auth Bypass Vulnerability

CVE-2026-7167 Overview

CVE-2026-7167 is a medium-severity input validation vulnerability affecting the Assassin Game Gaudire application. The flaw stems from missing validation of the email field during authentication and account registration. Attackers can register accounts using unverified or fabricated email addresses, bypassing identity controls intended to enforce one user per legitimate inbox. Successful exploitation enables mass creation of fraudulent accounts, which can be weaponized for spam distribution, abuse of in-app features, and circumvention of user-level rate limiting or moderation. The issue is tracked under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor and was disclosed through the Incibe CERT Security Notice.

Critical Impact
Authenticated attackers can mass-register accounts with fake email addresses, enabling spam campaigns, abuse of platform features, and bypass of per-user controls.

Affected Products

Assassin Game Gaudire application (authentication component)
Account registration and login workflows accepting the email parameter
Any deployment relying on email uniqueness for user-level abuse prevention

Discovery Timeline

2026-06-22 - CVE-2026-7167 published to NVD
2026-06-22 - Last updated in NVD database

Technical Details for CVE-2026-7167

Vulnerability Analysis

The vulnerability resides in the authentication layer of the Assassin Game Gaudire application. The system accepts the email field from client-submitted registration and authentication requests without verifying that the address is real, deliverable, or owned by the requester. No confirmation email, syntactic enforcement, or domain validation gates account activation. As a result, the application treats any string passed as email as a legitimate identity attribute. This breaks the implicit trust boundary that ties an account to a human-controlled inbox and weakens every downstream control that relies on email uniqueness.

Root Cause

The root cause is improper input validation on the email parameter, classified under CWE-200. The registration endpoint does not enforce email verification through an out-of-band confirmation link. It also lacks server-side format checks, disposable-domain filtering, and rate limiting on account creation. Because email ownership is never proven, the authentication boundary collapses to whatever credentials the attacker chooses to supply.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker scripts repeated POST requests to the registration endpoint, supplying arbitrary or randomly generated email strings for each account. Each request yields a usable account that can then authenticate against the platform. Attackers chain these accounts to distribute spam, inflate engagement metrics, vote-stuff, evade bans, or amplify subsequent attacks against other players. The vulnerability cannot be exploited to read or modify backend data directly, which aligns with the limited integrity and availability impact reflected in the scoring.

No verified public proof-of-concept code is available. Refer to the Incibe CERT advisory for additional technical context.

Detection Methods for CVE-2026-7167

Indicators of Compromise

Spikes in account creation volume from a small set of source IPs or autonomous systems.
Newly registered accounts using disposable, nonexistent, or syntactically invalid email domains.
Multiple accounts sharing User-Agent strings, device fingerprints, or registration timing patterns.
Outbound spam, abusive messages, or automated actions originating from recently created accounts.

Detection Strategies

Inspect web application logs for high-frequency POST requests to the registration endpoint without preceding browser navigation traffic.
Correlate registration events with mail server bounce logs to identify accounts whose confirmation emails are undeliverable.
Profile the entropy and domain distribution of registered email addresses to flag automated patterns.

Monitoring Recommendations

Forward authentication and registration telemetry to a centralized SIEM or data lake for behavioral baselining.
Alert on bursts of account creations that exceed historical norms per IP, subnet, or ASN.
Track post-registration behavior such as immediate messaging, friend requests, or content posting that suggests automated abuse.

How to Mitigate CVE-2026-7167

Immediate Actions Required

Enforce server-side email syntactic validation against RFC 5322 and reject addresses that fail.
Require out-of-band email confirmation before activating any new account or granting privileged actions.
Apply rate limiting and CAPTCHA challenges on the registration endpoint to disrupt automation.
Block known disposable and temporary email domains at the registration layer.

Patch Information

No vendor patch reference is published in the CVE record at the time of writing. Consult the Incibe CERT Security Notice for vendor coordination updates and apply any official Assassin Game Gaudire release that introduces email verification.

Workarounds

Place a web application firewall (WAF) rule in front of the registration endpoint to enforce request rate limits and CAPTCHA tokens.
Quarantine accounts whose email addresses have not been verified within a defined window and revoke their access to sensitive features.
Manually review and purge accounts created from suspicious domains or with implausible address formats.

bash

# Example WAF rate limit (ModSecurity-style) on the registration endpoint
SecRule REQUEST_URI "@beginsWith /api/register" \
  "id:1007167,phase:1,deny,status:429,\
   setvar:ip.reg_count=+1,expirevar:ip.reg_count=60,\
   chain"
  SecRule IP:REG_COUNT "@gt 5" \
    "msg:'CVE-2026-7167: registration rate limit exceeded'"