CVE-2026-78891 in Chrome
Summary
by MITRE • 08/26/2026
Buffer overflow in WebRTC in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as CVE-2024-3878 represents a critical buffer overflow condition within the WebRTC implementation of Google Chrome prior to version 152.0.7977.65. This flaw resides in the core media processing components that handle real-time communication protocols, specifically affecting how data buffers are allocated and managed during the parsing or decoding of multimedia streams. The root cause is a failure to properly validate input boundaries when processing crafted HTML pages containing maliciously constructed WebRTC payloads. When an attacker hosts such a page and induces a victim to visit it, the browser attempts to process the malformed media stream data. Due to insufficient bounds checking, the application writes beyond the allocated memory buffer, leading to heap corruption or stack overflow conditions depending on the specific code path triggered within the Chromium engine.
From a technical perspective, this vulnerability is classified under CWE-120, which denotes Buffer Copy without Checking Size of Input Classic Buffer Overflow. The exploitation vector relies heavily on social engineering tactics where the victim must interact with a malicious webpage that leverages JavaScript APIs to initiate WebRTC connections and inject malformed data packets. Although Chrome employs robust sandboxing mechanisms designed to isolate browser processes from the underlying operating system, buffer overflow vulnerabilities in high-privilege renderer or utility processes can sometimes allow attackers to achieve arbitrary code execution within the restricted environment. In this specific instance, the severity is rated as Medium by Chromium security standards because while the vulnerability allows for remote code execution inside the sandbox, bypassing the full isolation boundary typically requires additional exploitation techniques such as heap spraying or information leaks to gain control over critical function pointers and escape to host-level privileges.
The operational impact of successfully exploiting this vulnerability extends beyond simple data corruption. An attacker who achieves arbitrary code execution within the Chrome sandbox can potentially access sensitive user data stored in browser memory, including cookies, session tokens, and autofill information. Furthermore, if combined with other vulnerabilities or specific system configurations that weaken sandbox isolation, such as disabled site-isolation features or outdated operating systems lacking advanced mitigation techniques like Control Flow Integrity (CFI), the attacker might escalate privileges to execute code on the host machine. This could lead to full device compromise, installation of persistent malware, and lateral movement within a network if the compromised browser is used for corporate activities. The ability to execute arbitrary code remotely makes this vulnerability particularly dangerous in phishing campaigns or drive-by download attacks targeting users who visit maliciously crafted websites.
Mitigation strategies primarily involve immediate software updates. Users must upgrade Google Chrome to version 152.0.7977.65 or later, where the buffer overflow has been patched by implementing stricter input validation and memory management checks within the WebRTC module. For organizations managing large fleets of devices, deploying automated patching solutions is essential to ensure rapid remediation across all endpoints. Additionally, security administrators should enforce strict Content Security Policies (CSP) that restrict inline scripts and limit external resource loading where possible, reducing the attack surface for drive-by exploits. Enabling Chrome’s built-in sandbox features and ensuring they are not disabled by group policy or user configuration is also critical to maintaining isolation boundaries. Regular monitoring of browser security advisories and keeping all components up to date remain the most effective defenses against such zero-day style vulnerabilities that target widely used web standards like WebRTC.