Permission Risk Table

Every permission in the curated PERMISSION_TABLE, grouped by risk level. These are the exact classifications the zovo.one scanner applies when it audits an installed extension's manifest.

LOW

Least-privileged. No persistent broad access; scoped to an explicit user gesture or confined to the extension's own sandbox.

Permission	Description
activeTab	Grants temporary access to the current tab only when the user explicitly clicks the extension's action. No persistent background access to any site.
contextMenus	Adds items to the browser's right-click context menu. No page content access by itself.
storage	Stores extension data locally (synced/local). Confined to the extension's own sandbox; cannot read site data.
alarms	Schedules code to run at a future time. No content access by itself.
idle	Detects when the machine is idle or locked. No page content access.
notifications	Shows desktop notifications. No page content access.
power	Keeps the screen or system awake. No content access.
tts	Text-to-speech output. No content access.
unlimitedStorage	Removes the extension storage quota. No extra site access.
declarativeNetRequest	Blocks or modifies network requests via static rules (the MV3 content-blocker path). Less powerful than webRequest blocking, but can still read request URLs.

MEDIUM

Sensitive. Grants meaningful read/write access (history, downloads, per-site host permissions, the clipboard) but is not a blanket global grant.

Permission	Description
bookmarks	Reads and modifies the user's full bookmark tree.
history	Reads and clears the user's full browsing history.
downloads	Initiates, monitors, and opens downloads; can open arbitrary files from the download shelf.
downloads.open	Opens downloaded files on disk. Combined with a hostile download this can execute local content.
geolocation	Reads the user's GPS / IP-derived location (subject to a per-site permission prompt).
clipboardWrite	Writes to the system clipboard. Can overwrite a copied password or inject pasted content.
clipboardRead	Reads the system clipboard, which frequently contains copied passwords, tokens, or private text.
identity	Triggers OAuth sign-in and obtains the user's signed-in account email / profile and an auth token.
management	Lists, enables, disables, and uninstalls other installed extensions.
tabs	Reads the URL and title of every open tab and receives tab-update events. Effectively full browsing-session visibility.
tabGroups	Reads and modifies tab groups, exposing which sites the user clusters together.
topSites	Reads the user's most-visited sites (the new-tab shortcuts).
sessions	Reads recently closed tabs and windows across devices.
pageCapture	Saves the current page as an MHTML archive, capturing rendered content.
search	Sets the default search provider and issues queries.

Scoped host match-patterns (e.g. *://*.example.com/*, https://*.mybank.com/*) are also classified as Medium — they grant content access to one domain family rather than the entire web.

HIGH

Broad, persistent, cross-origin or sensitive-system access. Treat any extension requesting these as needing careful review.

Permission	Description
cookies	Reads and modifies all cookies for any site the extension has host access to, including session and auth cookies.
webRequest	Observes (and in MV2 could block) every network request and response, exposing full URLs, headers, and bodies including credentials.
debugger	Attaches the Chrome DevTools Protocol to a tab, giving full DOM, network, and JS execution control — effectively total control of the page.
nativeMessaging	Talks to a native application installed on the user's machine. Escapes the browser sandbox entirely.
fileSystem	Reads and writes files outside the browser sandbox (where granted by the platform).
<all_urls>	Requests host access to every site on the web. Combined with content scripts this means any page's content, forms, and credentials can be read.
*://*/*	Match pattern granting host access to every http/https URL. Equivalent in effect to <all_urls> for normal browsing.
http://*/*	Host access to every plain-http URL, including login pages and intranet sites.
https://*/*	Host access to every secure URL on the web.
file:///*	Host access to local files via the file:// scheme, subject to the "allow access to file URLs" toggle.
proxy	Configures the browser's proxy settings. A hostile extension can redirect all traffic through an attacker-controlled server.
privacy	Reads and changes privacy-related browser settings (do-not-track, third-party cookies, hyperlink auditing).
system.cpu	Reads detailed CPU metadata useful for device fingerprinting.
system.memory	Reads physical memory capacity, a device-fingerprinting signal.
system.storage	Reads attached storage device metadata and can eject devices.
system.network	Reads network interface metadata exposing the local network topology.
system.display	Reads display metadata (resolution, DPI) usable for fingerprinting.
vpnProvider	Configures a VPN (ChromeOS), which can redirect and intercept all network traffic.
enterprise.networkingAttributes	Reads detailed network attributes (ChromeOS enterprise), exposing internal network identity.
webNavigation	Receives the full navigation events of every frame in every tab, including the URL of every frame and redirect.
scripting	Injects arbitrary JavaScript into pages for which the extension has host permission — full page control at runtime (MV3 successor to tabs.executeScript).
contentSettings	Reads and modifies per-site content settings (cookies, javascript, plugins, mic, camera) for every origin.

Combinations matter

A single permission's level is only part of the picture. The genuinely dangerous pairings are:

• cookies + <all_urls> → can steal session tokens for every site.
• webRequest + <all_urls> → can read every request body, including submitted passwords.
• scripting + <all_urls> → can inject arbitrary JS into any page, including bank logins.
• nativeMessaging + anything → escapes the browser sandbox.

Use highest_risk to compute the dominant risk across a manifest, then surface the individual High entries for review. This is exactly what the zovo.one scanner does.