CVE-2019-11733

What it actually does

Bypasses the master password re-entry requirement for the copy-password context menu action on stored credentials when the master password was previously entered in the same browser session, allowing direct clipboard access to plaintext passwords.

Why it matters to the business

Stored credentials for multiple sites can be silently exfiltrated by anyone with brief access to an unlocked browser session, increasing risk of account takeover, data breach, and compliance violations; the issue has been public for years with no known widespread exploitation.

How an attack unfolds

An attacker with local or session access to a Firefox instance that has already prompted for the master password once opens the Saved Logins dialog, uses the copy context menu on any credential entry, and obtains the password in plaintext on the clipboard without further authentication.

How to fix it

Upgrade Mozilla Firefox to version 68.0.2 or later and Mozilla Firefox ESR to version 68.0.2 or later; after upgrade, change any passwords that may have been exposed and consider clearing the clipboard after use.

How to confirm the fix worked

Verify installed browser version is at least 68.0.2; confirm that the copy-password menu item now requires master-password re-entry even within the same session; review update logs and application manifests for the patched build.

Typical attack path

1. Obtain local or unattended access to a running Firefox process where the master password has already been entered once in the session
2. Navigate to the Saved Logins dialog
3. Right-click a stored login entry and select the copy-password menu item
4. Read the plaintext password from the clipboard or paste it elsewhere for exfiltration

How to detect it

Review browser update and crash logs for pre-68.0.2 versions; inspect clipboard history artifacts or paste operations from the browser process; no remote network indicators exist because exploitation requires local session access.

What your security team should do

• Prioritize patching all Firefox and Firefox ESR instances to 68.0.2 or newer immediately
• Enforce browser auto-update policies and inventory all managed endpoints for legacy versions
• Educate users to lock or close browsers when stepping away and to treat the clipboard as untrusted storage
• Monitor for any internal reports of unexpected password exposure and rotate high-value credentials