CVE-2026-12258: Hiperdino REST API Information Disclosure

CVE-2026-12258 Overview

CVE-2026-12258 is an information disclosure vulnerability affecting the Hiperdino REST v1.0 API. The flaw resides in the public customer/check endpoint, which accepts a telephone number or email address as input. When the submitted value matches a registered customer, the API returns the associated contact details, including the email address and telephone number. The endpoint enforces only a static bearer token for access, applies no rate limiting, and returns non-generic error responses. An attacker holding a valid bearer token can enumerate customer contact records at scale. The issue is classified under [CWE-284] Improper Access Control.

Critical Impact
Remote actors with a static bearer token can enumerate customer email addresses and phone numbers through the public customer/check endpoint without additional authentication.

Affected Products

Hiperdino REST API v1.0
customer/check public endpoint
Applications relying on the Hiperdino v1.0 backend for customer lookup

Discovery Timeline

2026-09-14 - CVE-2026-12258 published to NVD
2026-09-18 - Last updated in NVD database

Technical Details for CVE-2026-12258

Vulnerability Analysis

The Hiperdino REST v1.0 API exposes a customer/check endpoint that acts as a customer lookup service. The endpoint accepts a phone number or email address and returns the matching customer's contact information when a record exists. Authentication relies exclusively on a static bearer token shared across API consumers. There is no per-user authentication, no request throttling, and no uniform error response that would prevent an attacker from distinguishing valid from invalid inputs. An attacker who obtains the static token can iterate over telephone numbers or email lists and harvest confirmed customer contact details. The harvested data supports downstream phishing, smishing, credential stuffing, and account takeover campaigns targeting Hiperdino customers.

Root Cause

The root cause is improper access control on a sensitive lookup endpoint. The API treats knowledge of a static bearer token as sufficient authorization to query personal data belonging to any registered customer. No identity binding exists between the caller and the customer record being queried, and the endpoint discloses whether a value is registered through differential responses.

Attack Vector

Exploitation occurs remotely over the network. An attacker in possession of a valid static bearer token issues HTTP requests to the customer/check endpoint containing candidate phone numbers or email addresses. Registered values return the customer's contact record while unregistered values return a different response, enabling reliable enumeration. The absence of rate limiting allows the attacker to script large-scale queries. No user interaction on the victim side is required. Refer to the INCIBE Notice on Access Control Issues for the coordinated advisory.

Detection Methods for CVE-2026-12258

Indicators of Compromise

High-volume requests to the customer/check endpoint originating from a single client, IP range, or bearer token identifier.
Sequential or dictionary-style query patterns against phone number and email parameters.
Response payloads containing customer email and phone fields returned to unexpected consumers or geographies.

Detection Strategies

Baseline normal customer/check request rates per bearer token and alert on deviations that suggest enumeration.
Inspect API gateway logs for repeated 200 responses with varying query parameters from the same source.
Correlate bearer token usage across IP addresses to identify token sharing or leakage.

Monitoring Recommendations

Forward API gateway and web server logs to a centralized analytics platform for query-pattern analysis.
Track token issuance, rotation, and revocation events to detect stale or compromised credentials.
Alert on distinct-parameter cardinality per token per hour to surface enumeration behavior early.

How to Mitigate CVE-2026-12258

Immediate Actions Required

Restrict the customer/check endpoint to trusted internal consumers or require per-user authentication in addition to the bearer token.
Rotate the existing static bearer token and audit all systems that store or transmit it.
Implement rate limiting and account-lockout style protections on the endpoint to slow enumeration attempts.
Normalize responses so that valid and invalid lookups return identical status codes and payload shapes.

Patch Information

No vendor patch or fixed version has been published in the NVD entry at the time of writing. Consult the INCIBE Notice on Access Control Issues for vendor coordination status and follow-up guidance.

Workarounds

Place the customer/check endpoint behind a Web Application Firewall (WAF) rule that enforces request-rate thresholds per token and per source IP.
Bind API tokens to specific source IP ranges and rotate them on a short schedule until a fix is available.
Disable or block the endpoint at the gateway if it is not required for production traffic.

bash

# Example NGINX rate limiting for the vulnerable endpoint
limit_req_zone $http_authorization zone=customer_check:10m rate=5r/m;

location /rest/v1/customer/check {
    limit_req zone=customer_check burst=5 nodelay;
    limit_req_status 429;
    proxy_pass http://hiperdino_backend;
}