# Private client content leaks through a lower-trust display or sharing channel

A private marker appears in a notification, background snapshot, clipboard or another user-visible channel outside its promised audience.

**Candidate CWE:** Map the actual root cause once established.

## Test hypothesis

Seed a private/public fixture pair and compare lock, background and account-switch states through the normal OS UI. Obtain the marker with only the stated observer privileges.

## Evidence required

Capture exact app/OS version, privacy settings, content ownership, reader prerequisites, state transition and the smallest marker exposure. Classify the actual display, notification, clipboard or sharing-channel mechanism; confidentiality loss alone does not establish a specific CWE root cause.

## Rule out false positives

Missing screenshot flags, intended account-owner display, explicitly granted accessibility authority, or a deliberate user-enabled notification preview may not violate the product's security contract.

## Playbook and command references

- [Client storage, logs, backup and transport trust](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/client-storage-transport.html) — Measure where sensitive client state goes, who can retrieve it, and whether transport rejects invalid peers.
- [iOS signing capabilities, links and protected data](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/ios-boundaries.html) — Connect entitlements and application groups to actual callers, URL transitions and protected key use.
- [Android components, intents and deep links](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/android-components.html) — Trace ordinary-app inputs through exported components, URI grants and links to one protected operation.

[Find the associated command snippets](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/commands.html?q=Client%20storage%2C%20logs%2C%20backup%20and%20transport%20trust)

## Referenced by these target playbooks

[Mobile](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/mobile.html) · [Desktop & extensions](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/desktop.html)

## Report checklist

- [ ] Capture the affected version, configuration, identities, and object ownership.
- [ ] Preserve a valid baseline and a negative control.
- [ ] Reproduce the forbidden data access, action, or state change on controlled fixtures.
- [ ] Explain the intended security rule and why the observed behavior violates it.
- [ ] State prerequisites, uncertainty, cleanup, and the smallest demonstrated impact.

## Conditional ATT&CK mapping

No direct ATT&CK mapping selected. Record the weakness and demonstrated impact without forcing an adversary-behavior classification. See the [mapping guide](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/attack.html).

## Primary references

- [OWASP MASVS-STORAGE-2: unintended data leakage](https://mas.owasp.org/MASVS/controls/MASVS-STORAGE-2/)

[Back to the complete vulnerability catalog](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/vulnerabilities.html)