ChromeWeb browser · Google
CVE-2021-21125
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedInsufficient policy enforcement in File System API in Google Chrome on Windows prior to 88.0.4324.96 allowed a remote attacker to bypass filesystem restrictions via a crafted HTML page.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceGoogle Chrome on Windows had insufficient policy enforcement in its File System API prior to version 88.0.4324.96. A remote attacker could craft a malicious HTML page to bypass filesystem restrictions and access files outside the intended sandboxed directory, potentially allowing unauthorized read/write access to the local filesystem.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
ChromeWeb browser
< 88.0.4324.96< 88.0.705.50CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed browser and get its versionOpen Chrome or Edge, click the menu (three dots) in the top right, then go to Help > About Google Chrome (or About Microsoft Edge). The version number is displayed on that page.Affected if Any version below 88.0.4324.96 for Chrome or below 88.0.705.50 for Edge Chromium.
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Compare installed version to affected rangesNote the full version number (for example, 88.0.4324.96) and compare it numerically against the affected versions: Chrome < 88.0.4324.96 or Edge < 88.0.705.50.Affected if The installed version is lower than 88.0.4324.96 for Chrome or lower than 88.0.705.50 for Edge.
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Check if File System API is in useThis vulnerability exists in the browser's File System API implementation itself - no specific configuration or feature flag needs to be enabled. The vulnerability is triggered when a webpage uses the File System API to request file access.Affected if Any use of the File System API by websites running in the browser on a vulnerable version.
A user is affected if they are running Google Chrome version below 88.0.4324.96 or Microsoft Edge Chromium version below 88.0.705.50 on Windows.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data88.0.705.5088.0.4324.96
Update Google Chrome to version 88.0.4324.96 or later to patch the File System API policy enforcement vulnerability. Organizations should deploy browser updates through their patch management infrastructure and verify completion across Windows endpoints.
Fix this in Chrome
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21125 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-21125 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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