CVE-2026-92861: Ticket Ryutsu Center Credential Exposure

CVE-2026-92861 Overview

CVE-2026-92861 affects the Android application "Ticket Ryutsu Center" distributed through the Google Play Store. The application contains hard-coded credentials [CWE-798] that an attacker with local access to the device or the application package can extract. The exposed credentials include an API key used by the application to communicate with backend services. Successful exploitation enables unauthorized use of the embedded API key against the vendor's service. The issue is tracked by JPCERT/CC under advisory JVN#53292492.

Critical Impact
An attacker who extracts the embedded API key can impersonate the Android application when calling backend APIs, enabling unauthorized access to protected resources tied to that key.

Affected Products

Android application jp.co.ticket ("Ticket Ryutsu Center") distributed via Google Play
Backend API endpoints that trust the embedded API key for request authentication
Any downstream service that relies on the leaked API key for authorization

Discovery Timeline

2026-10-08 - CVE-2026-92861 published to the National Vulnerability Database
2026-10-08 - Last updated in NVD database

Technical Details for CVE-2026-92861

Vulnerability Analysis

The Android application ships with credentials embedded directly in the distributed APK. Because APK files can be downloaded from the Play Store and unpacked with standard tooling, any user can inspect the contents of the application. Attackers extract the embedded API key by decompiling the application bytecode, inspecting resource files, or dumping strings from compiled binaries. Once the key is recovered, the attacker can use it outside the application to issue authenticated requests to the vendor's backend. The flaw is categorized as Use of Hard-coded Credentials [CWE-798] and classified as a local attack because recovery of the key requires access to the installed application package.

Root Cause

The root cause is the inclusion of a static API key within the shipped application artifact rather than fetching it at runtime through an authenticated channel tied to a user identity. Android applications distributed through public stores cannot be treated as trusted secret containers. Any secret compiled into the APK is recoverable by an attacker who downloads the package.

Attack Vector

An attacker obtains the APK, either from the device or from a public mirror of the Play Store listing. The attacker then uses standard reverse-engineering tools such as apktool, jadx, or strings to inspect decompiled Smali, Java source, string resources, and native libraries. The embedded API key is recovered and reused in attacker-controlled HTTP clients to call backend endpoints without the application in the loop. No privileges are required on the vendor's infrastructure, and no user interaction is required for key extraction.

No verified exploit code is published for CVE-2026-92861. Refer to the JVN
advisory for vendor-provided details on the affected version and fixed build.

Detection Methods for CVE-2026-92861

Indicators of Compromise

API requests to the vendor backend originating from non-mobile User-Agent strings while presenting the application's API key
Request patterns that deviate from normal mobile client behavior, such as high request rates or missing expected headers
API key usage from geographic regions or IP ranges that do not match the application's user base

Detection Strategies

Review backend access logs for the API key to identify callers that are not legitimate mobile clients
Instrument the backend to log client fingerprints such as TLS JA3, User-Agent, and header ordering, and alert on anomalies
Scan published APK versions in CI with secret-detection tools such as truffleHog or gitleaks to catch embedded keys before release

Monitoring Recommendations

Monitor the Google Play listing jp.co.ticket and advisory JVN#53292492 for a fixed version
Track API key usage volumes and alert on sudden deviations that may indicate credential abuse
Correlate authentication events with device attestation signals where available

How to Mitigate CVE-2026-92861

Immediate Actions Required

Rotate the exposed API key on the backend and invalidate the previous value
Update the Android application to a version that no longer embeds static credentials
Restrict the scope and rate limits of the API key on the server side until a fix is deployed

Patch Information

Refer to the JVN Security Advisory JVN#53292492 and the Google Play listing for jp.co.ticket for the vendor-supplied fixed version. Upgrade all installed instances to the patched release and confirm the application no longer contains static credentials by inspecting the new APK.

Workarounds

Issue short-lived, per-user tokens from an authentication service rather than relying on a static API key shipped in the client
Enforce server-side rate limiting and anomaly detection on requests presenting the exposed key until rotation is complete
Apply Google Play Integrity API or equivalent attestation to require that API requests originate from a genuine, unmodified application instance

bash

# Example server-side rate limit while the key is being rotated
# nginx snippet applied to the API endpoint serving mobile clients
limit_req_zone $http_x_api_key zone=mobilekey:10m rate=10r/s;

location /api/ {
    limit_req zone=mobilekey burst=20 nodelay;
    proxy_pass http://backend;
}