CVE-2024-0333 is a high-severity insufficient data validation vulnerability in the Extensions component of Google Chrome, fixed in version 120.0.6099.216, that could let an attacker in a privileged network position install a malicious extension through a crafted HTML page. Google shipped the fix in a stable channel update on January 9, 2024. If you manage Chrome across an organization, this one is worth understanding because it turns a network-level foothold into browser-level persistence.
What CVE-2024-0333 is
The vulnerability sits in how Chrome validates extension-related data. Under normal conditions, installing an extension is a deliberate, consent-gated action: a user visits the Web Store or explicitly loads an extension. CVE-2024-0333 is an insufficient validation gap where the browser did not properly validate certain extension data during network operations, opening a path to inject a malicious extension-installation flow without the usual explicit user consent.
Google classified the Chromium security severity as High. It was addressed in Chrome 120.0.6099.216, and because Chromium powers many other browsers, downstream projects such as Microsoft Edge tracked and shipped the corresponding fix as well.
The attack vector: why "privileged network position" is the catch
The exploitation precondition is the important part. This is not a drive-by that any random website can trigger. The attacker needs a privileged network position, meaning they can observe or modify the victim's traffic, for example from a compromised router, a rogue access point, or a man-in-the-middle vantage point on a shared network.
From that position, the attacker serves or tampers with an HTML page the victim loads, and the insufficient validation lets the crafted content drive an extension installation that should have required explicit approval. The chain looks like this:
1. Attacker gains a man-in-the-middle position (e.g., malicious Wi-Fi).
2. Victim on Chrome < 120.0.6099.216 browses to a page the attacker controls or modifies.
3. Crafted HTML exploits the validation gap in the Extensions component.
4. A malicious extension is installed without the normal consent gate.
5. The extension can now read/modify browsing data, persist, and phone home.
The payoff for the attacker is significant, because a malicious extension is a durable foothold inside the browser: it can read page content, capture form input, and survive tab and session changes.
Affected versions and the fix
The vulnerability affects Google Chrome prior to 120.0.6099.216. The remediation is simply to run Chrome at or above that version.
To confirm your version:
1. Open Chrome and navigate to chrome://settings/help
2. Chrome checks for and applies updates automatically.
3. Confirm the version reads 120.0.6099.216 or higher, then relaunch.
For managed fleets, do not rely on users to relaunch. Use your management tooling, Chrome Browser Cloud Management, Group Policy, or your MDM, to enforce a minimum version and to require relaunch within a bounded window.
Reducing exposure beyond the patch
Patching closes CVE-2024-0333 specifically, but the attack model, a network attacker abusing a browser flaw, argues for a few standing controls.
Enforce HTTPS everywhere. A privileged network position is far less useful against traffic the attacker cannot read or modify. HSTS and modern TLS shrink the window for content tampering.
Control extension installation by policy. Chrome enterprise policy lets you allowlist approved extensions and block everything else with ExtensionInstallBlocklist set to * plus an explicit ExtensionInstallAllowlist. Even if an installation flow is triggered, an extension outside the allowlist will not load.
Manage update latency. The gap between a fix shipping and a fleet actually running it is where real risk lives. Track your Chrome version distribution and treat a long tail of outdated clients as an open finding.
Be cautious on untrusted networks. The classic advice, avoid sensitive browsing on open Wi-Fi or use a trusted VPN, directly addresses the man-in-the-middle precondition this CVE relies on.
Where browser CVEs fit in a broader program
A single browser CVE is a small piece of a much larger client-side attack surface, and the right response is process rather than panic. Fast, verifiable patch rollout is the control that pays off across the steady stream of Chrome fixes each release brings, not just this one. The same discipline that keeps server-side dependencies current, inventory, prioritize by exploitability, patch, verify, applies to the browser fleet. If you want to build that muscle across your whole stack, our security academy walks through building a repeatable vulnerability response workflow.
FAQ
What is the severity of CVE-2024-0333?
Google assigned it a Chromium security severity of High. It is an insufficient data validation issue in the Extensions component.
Which Chrome version fixes CVE-2024-0333?
It is fixed in Chrome 120.0.6099.216, released in the stable channel on January 9, 2024. Any earlier version is affected.
Can any website exploit this?
No. Exploitation requires the attacker to hold a privileged network position, such as a man-in-the-middle on the victim's network, so they can serve or modify the crafted HTML page. That precondition limits, but does not eliminate, real-world risk.
How do I protect a managed Chrome fleet?
Enforce a minimum Chrome version through your management tooling, require timely relaunch, and use enterprise extension policies to allowlist approved extensions so unauthorized ones cannot load even if an install flow is triggered.