CVE-2026-4243 Overview
CVE-2026-4243 identifies a credential storage weakness in the La Nacion Android application version 10.2.25. The flaw resides in source/app/lanacion/clublanacion/BuildConfig.java within the app.lanacion.activity component. The API_KEY_WEBSOCKET_CV argument is stored without protection, exposing a WebSocket credential that an attacker with local access can recover. The issue is categorized under [CWE-255] (Credentials Management Errors). Exploitation requires local access and high attack complexity, which limits practical impact. The vendor was contacted prior to disclosure but did not respond. A public exploit reference has been published through VulDB.
Critical Impact
Local attackers who can read application resources may extract the embedded WebSocket API key and reuse it to abuse backend services, potentially enabling resource exhaustion against the WebSocket endpoint.
Affected Products
- La Nacion App for Android, version 10.2.25
- Component: app.lanacion.activity
- Source file: source/app/lanacion/clublanacion/BuildConfig.java
Discovery Timeline
- 2026-03-16 - CVE-2026-4243 published to NVD
- 2026-04-29 - Last updated in NVD database
Technical Details for CVE-2026-4243
Vulnerability Analysis
The La Nacion Android application embeds a WebSocket API key (API_KEY_WEBSOCKET_CV) directly into the compiled BuildConfig.java file. Android build tooling places BuildConfig constants into the application's DEX bytecode. Anyone with access to the installed APK can decompile it and retrieve the literal value. Because the key authenticates the client against a backend WebSocket service, recovery of the key grants the attacker the same trust level as the legitimate mobile client.
According to the public analysis referenced by VulDB, the recovered credential can be reused to open many concurrent WebSocket sessions, raising the risk of distributed denial-of-service activity against the server side.
Root Cause
The root cause is unprotected storage of credentials inside a build-time constant. Storing secrets in BuildConfig fields, string resources, or other static fields does not provide confidentiality because the values are present as plaintext in the APK. The mobile client model assumes attackers can fully inspect application binaries, so any long-lived shared secret distributed this way is effectively public.
Attack Vector
The attack vector is local. An attacker obtains the APK from the device or from a public mirror and runs a standard decompiler such as apktool or jadx against the package. The attacker locates the BuildConfig class inside the app.lanacion.activity namespace and reads the API_KEY_WEBSOCKET_CV string. The recovered key is then used outside the app to authenticate scripted WebSocket clients. High attack complexity reflects the manual tooling and reverse engineering required, not a cryptographic barrier.
No verified exploit code is published for this entry; technical details are summarized in the Notion WebSocket Leak Analysis and the VulDB CTI ID #351185 record.
Detection Methods for CVE-2026-4243
Indicators of Compromise
- Multiple concurrent WebSocket sessions to the La Nacion backend originating from non-mobile IP ranges or datacenter ASNs.
- WebSocket authentication events using the API_KEY_WEBSOCKET_CV value from clients lacking expected mobile user-agent or device attestation headers.
- Sudden spikes in WebSocket connection rate or message volume that do not correlate with normal application telemetry.
Detection Strategies
- Perform static analysis of mobile builds for hardcoded secrets in BuildConfig, resource files, and assets. Tools such as MobSF or truffleHog can be added to the CI/CD pipeline.
- Add server-side anomaly detection on the WebSocket gateway that flags reuse of the same API key from divergent geolocations or non-mobile clients.
- Monitor public paste sites and APK mirrors for redistribution of the affected APK version.
Monitoring Recommendations
- Log all WebSocket handshake events with key identifier, source IP, ASN, and device attestation result for retention and correlation.
- Alert on connection-rate thresholds per API key to surface abuse patterns consistent with denial-of-service preparation.
- Track mobile application version distribution to identify devices still running version 10.2.25 after a fix is published.
How to Mitigate CVE-2026-4243
Immediate Actions Required
- Rotate the API_KEY_WEBSOCKET_CV value and revoke the leaked credential on the WebSocket backend.
- Implement server-side rate limiting and per-key connection caps on the WebSocket endpoint to contain abuse.
- Require device attestation, such as Google Play Integrity API, before issuing session credentials to mobile clients.
Patch Information
The vendor did not respond to the disclosure, and no official patch is referenced in the NVD record. Users should monitor the VulDB ID #351185 entry and the Google Play listing for an updated release that removes the embedded credential.
Workarounds
- Replace the static API key with short-lived tokens issued after user authentication, so compromise of one client does not expose a global secret.
- Move secrets out of BuildConfig and into a server-mediated token exchange protected by TLS and certificate pinning.
- Apply server-side allow lists or anomaly scoring to reject connections that present the legacy key after rotation.
# Example: revoke and rotate the leaked WebSocket key on the backend
# (illustrative configuration, adapt to your gateway)
wscli keys revoke --name API_KEY_WEBSOCKET_CV
wscli keys create --name API_KEY_WEBSOCKET_CV_v2 --ttl 3600 --rate-limit 30/min
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
