# Page message borrows unintended browser-extension authority

An ordinary web page reaches a privileged extension action through insufficient message sender or argument validation.

**Candidate CWE:** [CWE-441](https://cwe.mitre.org/data/definitions/441.html) · [CWE-863](https://cwe.mitre.org/data/definitions/863.html)

## Test hypothesis

Capture one intended page-to-extension action; repeat through the same shipped listener from a second controlled origin or with one changed synthetic resource. Observe the protected marker or reversible action and compare a rejected sender control.

## Evidence required

Preserve installed ID/version, real page entry, browser-provided sender metadata, body fields, permission grants, final API call and receiving principal.

## Rule out false positives

Broad host permissions, an external messaging entry or extension-console access alone is not the flaw. Public data and deliberately delegated page actions may be intended.

## Playbook and command references

- [Browser extensions: message authority and document lifetime](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/extension-message-boundaries.html) — Trace real page messages into extension capabilities and test sender identity, navigation races, permission changes and worker restarts.
- [Desktop IPC, Electron bridges and native protocols](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/desktop-ipc.html) — Follow page, file and local-process inputs into privileged desktop capabilities with a realistic caller.
- [Browser execution, cross-origin reads, and forged actions](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/browser-trust.html) — Use real browser behavior to distinguish XSS, CSRF, CORS, and messaging failures from header-only leads.

[Find the associated command snippets](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/commands.html?q=Browser%20extensions%3A%20message%20authority%20and%20document%20lifetime)

## Referenced by these target playbooks

[Desktop & extensions](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/desktop.html) · [Web & API](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/web-api.html) · [OSS & self-hosted](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/oss.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

- [Chrome extension message passing](https://developer.chrome.com/docs/extensions/develop/concepts/messaging)
- [Chrome cross-origin request security](https://developer.chrome.com/docs/extensions/develop/concepts/network-requests)

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