Extension Asking for Cookies Permission

Extension asking for cookies permission

Short answer

The cookies permission lets an extension read, create and modify cookies for permitted sites. Cookies often contain session identifiers, so this access can be powerful. Legitimate uses include session managers, testing tools and account switchers. The access should match a clear feature and a transparent data policy.

Drop an extension package hereor choose a file from your deviceChoose a fileSupported: CRX, XPI, ZIP, manifest.json. Maximum size: 25 MB.

Processed locallyCode is never executed

Your file stays in this browser. Parsing happens in a Web Worker; the extension code is read, never executed.

What the scan checks

Permissions, host access, content scripts, background scripts, CSP, externally_connectable, web-accessible resources, JavaScript patterns, referenced domains and risk categories.

MV3MV2CRXXPIZIPJSON

Static analysis shows references and patterns. It cannot prove that network activity happened or that an extension is malicious.

Compare two versions

See permission, domain and finding changes between two packages.

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What the permission actually allows

With cookies and matching host permissions, an extension can query cookie stores, read names and values, set cookies and listen for changes. It can reach cookies for the sites its host permissions cover, which may be all sites.

This is broader than document.cookie access in a content script. The API can see HttpOnly cookies that page scripts cannot read.

Legitimate and concerning patterns

A session manager may list and switch accounts, a developer tool may inspect authentication, and a privacy tool may clear cookies on a schedule. These can be legitimate, especially when host access is narrow and the behavior is visible.

Concern rises when a simple utility requests cookies plus all-site access, when cookie values are sent to analytics or unknown domains, or when the privacy policy does not explain retention.

Cookie access signals
Signal	Interpretation	Next step
cookies + specific hosts	Scoped account feature	Check the feature description
cookies + all_urls	Broad access to sessions	Review code and domains closely
cookie change listeners	Monitors session changes	Check what is logged or sent
document.cookie in a script	Page-level cookie access	Check host matches and data flow

Reducing cookie exposure

Prefer extensions with specific host permissions. Remove cookie-related extensions you do not actively use. If you need one, consider a separate profile for sensitive accounts and review the extension after updates.

A permission is not proof of misuse. It is a reason to verify the feature and the destination of any cookie data.

Frequently asked questions

Can an extension read all my cookies?

Only for sites covered by its host permissions and when it has the cookies permission. With broad host access, that can include most sites you use.

Can it read HttpOnly cookies?

The extension cookies API can access cookies that page scripts cannot, including HttpOnly cookies, subject to permissions and browser rules.

Are cookie manager extensions safe?

They can be useful, but they need powerful access. Choose one with narrow host permissions, a clear policy and a trustworthy publisher.

Last reviewed: October 31, 2026