Notification Content Disclosure via Alternate Surface

← Privacy (OWASP Mobile M6)

notification_alternate_surface_disclosure   MEDIUM

Description

Sensitive notification content that is redacted on the lock screen is rendered in full on a secondary presentation surface (desktop / DeX mode, widget, companion display) that skips the redaction / access-control boundary, so someone with access to that surface reads hidden notification contents (Samsung DeX CVE-2026-21006 class).

How it works

Sensitive notification content that is redacted on the lock screen is rendered in full on a secondary presentation surface (desktop / DeX mode, a home-screen widget, a companion display) that skips the redaction/access-control boundary, so anyone with access to that surface reads the hidden contents (the Samsung DeX CVE-2026-21006 class). This is an offline, deterministic simulation: a notification carries a public (redacted) and a private (full) form, and the vulnerable alternate-surface renderer emits the full private content, ignoring the visibility policy the lock screen honors. The secure path applies the same redaction policy on every unauthenticated surface, so the alternate surface shows only the redacted form until authenticated.

How to exercise it. DVMA is the harness - open this module from the home index and tap the demo action. The screen ships the malicious input and simulates the attacker (e.g. the companion app, crafted intent, or scanned payload) in-process, and the evidence panel prints the proof. The Tools (optional) and Attack inputs below are only needed to reproduce the exploit end-to-end on a real device.

Exploit steps

1. Set up. Build DVMA with a flavor that enables the Privacy (OWASP Mobile M6) category (e.g. --dart-define-from-file=config/flavors/dev.json) and run on an emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: Android: adb, scrcpy · iOS: idevicescreenshot, QuickTime screen recording.
2. Locate the target. From the home index, open Notification Content Disclosure via Alternate Surface (notification_alternate_surface_disclosure). The How it works section above describes this module’s specific weakness; the screen states the intended-secure behavior and exposes the vulnerable action.
3. Exploit. Trigger the data-access/telemetry path and confirm sensitive data is collected, transmitted, or associated without the required consent / transparency prompt.
4. Observe the evidence. Trigger the vulnerable action and read the evidence panel - it prints the concrete proof (leaked value, accepted replay, executed payload, or unauthorized result).
5. Contrast with the secure path. Run the module’s secure/hardened action (where provided) and confirm the same attack is rejected - this is what a correct implementation should do.
6. Map it back. Cross-reference the MASTG v2 test(s) MASTG-TEST-0315 for the canonical procedure and remediation.

Tools (optional)

Android

• adb
• scrcpy

iOS

• idevicescreenshot
• QuickTime screen recording

Real-world references

Concrete public disclosures that match this vulnerability class:

• CVE-2026-21006 (Samsung DeX hidden notification content disclosure)