Home > News > 🚨 Urgent: Chrome Zero-Day Vulnerability CVE-2023-4863 Unveiled! 4th in 2023!

🚨 Urgent: Chrome Zero-Day Vulnerability CVE-2023-4863 Unveiled! 4th in 2023!


Google Responds to Chrome Zero-Day Vulnerability CVE-2023-4863, Credits Apple and Citizen Lab for Discovery

In a swift action that underscores the perpetual arms race against cyber threats, Google recently launched a crucial update for its Chrome browser, patching the Chrome Zero-Day Vulnerability CVE-2023-4863. This marked the fourth zero-day vulnerability in Chrome that has been addressed this year.

What is Chrome Zero-Day Vulnerability CVE-2023-4863?

Chrome Zero-Day Vulnerability CVE-2023-4863 is a high-risk, heap buffer overflow issue affecting the WebP component of the browser. WebP is an advanced image format offering enhanced compression and quality, overshadowing its predecessors, JPEG and PNG. Almost all contemporary browsers, like Firefox, Safari, Edge, and Opera, support this image format.

For those unfamiliar with the term, a “heap buffer overflow” occurs when an application tries to store more data in a heap-allocated memory buffer than it can actually hold. This can lead to application crashes and possibly open the door for hackers to execute arbitrary code on the victim's system.

Google's advisory points out that they are aware that an exploit exists for this vulnerability “in the wild,” making it imperative for users to update their browsers immediately.

For a more technical explanation of heap buffer overflow issues, check out this guide.

Who Discovered the Vulnerability?

The discovery of Chrome Zero-Day Vulnerability CVE-2023-4863 was credited to Apple's Security Engineering and Architecture (SEAR) and Citizen Lab at The University of Toronto’s Munk School. Citizen Lab frequently exposes commercial spyware activities, which leads to the speculation that this vulnerability might have been exploited by one such spyware vendor. Google's policy states that no bug bounty will be rewarded for this particular flaw.

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Why is the Vulnerability Critical?

Heap buffer overflow issues like Chrome Zero-Day Vulnerability CVE-2023-4863 are perilous because they can be exploited to bring down an application and potentially provide a gateway for hackers to run arbitrary code. This is particularly alarming when the application in question is a browser, as it serves as a gateway to the Internet and holds a wealth of information, including login credentials and personal data.

Also, the fact that Citizen Lab and Apple SEAR were the entities that reported this flaw raises eyebrows. Commercial spyware companies often offer complex exploit chains that include Chrome vulnerabilities, targeting not only desktop users but also Android mobile users.

Here is an insightful article on why browser vulnerabilities are a critical issue.

Google’s Chrome Patch Details

Google responded by releasing an emergency security update to mitigate Chrome Zero-Day Vulnerability CVE-2023-4863. Chrome users should now look for version 116.0.5845.187 for macOS and Linux, and as versions 116.0.5845.187/.188 for Windows. It is crucial to apply this update as soon as possible to safeguard against potential exploits.

To update your Chrome browser, follow these steps.

The Landscape of Zero-Day Vulnerabilities in 2023

It is worth noting that CVE-2023-4863 is the fourth zero-day vulnerability that Google has addressed in Chrome this year. Earlier, they had patched CVE-2023-3079 (type confusion in the V8 engine) in June and CVE-2023-2033 (type confusion in the V8 engine) and CVE-2023-2136 (integer overflow in Skia) in April. This series of zero-day vulnerabilities underscores the ever-evolving threat landscape and the necessity for timely updates and patches.

For a detailed timeline of zero-day vulnerabilities, you can visit this resource.


Chrome Zero-Day Vulnerability CVE-2023-4863 is a glaring example of the constant cat-and-mouse game between cybersecurity experts and cybercriminals. As users, the best defense against such threats is to keep software and applications up-to-date. Always be wary of advisories from reputable sources and act upon them promptly to keep your digital environment secure.

For more tips on securing your online browsing experience, check out this guide.

By being proactive in our approach to cybersecurity, we can make it increasingly challenging for cybercriminals to exploit vulnerabilities, thereby contributing to a safer online community for everyone.


What is Chrome Zero-Day Vulnerability CVE-2023-4863?

This is a critical severity vulnerability identified in Google Chrome, specifically a heap buffer overflow issue in the WebP component. Google has released an emergency security update to address this vulnerability.

Who discovered this vulnerability?

The vulnerability was reported by Apple Security Engineering and Architecture (SEAR) and The Citizen Lab at The University of Toronto's Munk School.

Why is this vulnerability considered ‘critical'?

Heap buffer overflow issues can allow attackers to crash an application and potentially execute arbitrary code, thus severely compromising user security.

How many zero-day vulnerabilities have been found in Chrome this year?

CVE-2023-4863 is the fourth zero-day vulnerability that Google has patched in Chrome in the year 2023.

What is WebP?

WebP is an image format that offers better compression and quality compared to JPEG and PNG formats. It's supported by all modern browsers, including Chrome, Firefox, Safari, Edge, and Opera.

Are there any exploits for this vulnerability?

Yes, Google is aware that an exploit for this vulnerability exists in the wild, but details about the exploit have not been disclosed.

What steps should I take to protect myself?

Update your Chrome browser to the latest version immediately. If you're using Chrome version 116.0.5845.187 for macOS and Linux or versions 116.0.5845.187/.188 for Windows, you're protected.

Who is suspected to exploit this vulnerability?

Though not confirmed, the involvement of SEAR and Citizen Lab suggests that the vulnerability could potentially be exploited by commercial spyware vendors.

What should I do if I suspect my system is compromised?

Run a full system scan using a reliable antivirus program, and also change all your passwords, especially for sensitive accounts like email and banking.

How do I report suspected exploitation of this vulnerability?

You can report security vulnerabilities directly to Google and also to local authorities for further investigation.

Will there be a bug bounty for this?

No, per Google’s policy, no bug bounty will be handed out for this flaw.

Is this vulnerability related to other recent security threats?

Yes, this vulnerability was discovered just days after Apple announced fixes for zero-day vulnerabilities in iOS and macOS. Both were discovered by Citizen Lab during the analysis of exploitation activities linked to commercial spyware vendors.


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