CVE-2026-9119: Google Chrome WebRTC Buffer Overflow Flaw

CVE-2026-9119 Overview

CVE-2026-9119 is a heap buffer overflow vulnerability in the WebRTC component of Google Chrome versions prior to 148.0.7778.179. A remote attacker can exploit this flaw by serving a crafted HTML page to a target browser. Successful exploitation allows arbitrary code execution within the Chrome sandbox. The Chromium security team rated this issue as High severity.

The vulnerability affects the Web Real-Time Communication (WebRTC) stack, which handles peer-to-peer audio, video, and data channels in the browser. Because WebRTC processing is triggered by web content, exploitation requires only that a user visit a malicious page or load attacker-controlled content in an iframe.

Critical Impact

Remote attackers can execute arbitrary code inside the Chrome renderer sandbox by luring users to a crafted HTML page that triggers a heap buffer overflow in WebRTC.

Affected Products

• Google Chrome Desktop versions prior to 148.0.7778.179
• Chromium-based browsers incorporating the vulnerable WebRTC code
• Applications embedding affected Chromium WebRTC components

Discovery Timeline

• 2026-05-20 - CVE-2026-9119 published to NVD
• 2026-05-20 - Last updated in NVD database

Technical Details for CVE-2026-9119

Vulnerability Analysis

The flaw is a heap buffer overflow [CWE-122] in the WebRTC implementation shipped with Google Chrome. Heap buffer overflows occur when code writes past the bounds of a heap-allocated buffer, corrupting adjacent memory structures. In a browser context, attackers can shape heap layout through scripted allocations to place exploitable objects next to the overflowed buffer.

WebRTC parses untrusted media and signaling data from remote peers and from JavaScript APIs exposed to web pages. An attacker controlling a malicious page can invoke the relevant WebRTC APIs with crafted parameters to trigger the overflow. The Chromium issue tracker entry references this as a memory safety defect addressed in the stable channel update.

Root Cause

The root cause is improper bounds enforcement during a WebRTC heap allocation or copy operation. When the input length exceeds the size assumed by the allocation logic, the write extends beyond the destination buffer. This corrupts heap metadata or adjacent objects, providing primitives for control-flow hijacking or type confusion.

Attack Vector

Exploitation requires a victim to load attacker-controlled HTML. The attacker hosts a page that uses WebRTC JavaScript APIs (such as RTCPeerConnection or related data channel interfaces) to feed crafted input into the vulnerable code path. User interaction is required, consistent with the UI:R component of the CVSS vector. Code execution is confined to the renderer sandbox absent a chained sandbox escape.

No public proof-of-concept exploit is referenced in the available advisory data. Technical specifics are tracked in the Chromium Issue Tracker Entry and the Google Chrome Desktop Update.

Detection Methods for CVE-2026-9119

Indicators of Compromise

• Chrome renderer process crashes with heap corruption signatures originating in WebRTC modules
• Unexpected child processes spawned from chrome.exe renderer processes following navigation to untrusted sites
• Outbound connections from renderer processes to unknown signaling or STUN/TURN endpoints immediately after visiting suspicious pages

Detection Strategies

• Inventory installed Chrome versions across managed endpoints and flag any build earlier than 148.0.7778.179
• Monitor browser process telemetry for anomalous memory access violations and renderer crashes referencing WebRTC libraries
• Correlate web proxy logs with renderer crash events to identify domains hosting exploit content

Monitoring Recommendations

• Enable browser crash reporting and forward dumps to a centralized analysis pipeline
• Track Chrome version compliance through endpoint management tooling and alert on stale installations
• Watch for post-exploitation behavior such as unexpected file writes, credential access, or lateral movement initiated from browser child processes

How to Mitigate CVE-2026-9119

Immediate Actions Required

• Update Google Chrome to version 148.0.7778.179 or later on all desktop endpoints
• Restart browser sessions after the update to ensure the patched binary is loaded into memory
• Apply equivalent updates to Chromium-based browsers and embedded WebRTC components as vendors release fixes

Patch Information

Google released the fix in the stable channel update documented at the Google Chrome Desktop Update. Administrators should validate that managed Chrome deployments have rolled forward to 148.0.7778.179 or a later build. Enterprises using Chrome Browser Cloud Management or group policy should confirm auto-update policies are not blocking the patched version.

Workarounds

• Disable WebRTC features through enterprise policy where business workflows do not require peer-to-peer media
• Restrict access to untrusted websites using DNS or proxy-based web filtering until patching is complete
• Use browser isolation or sandboxed virtual environments for high-risk browsing activities

# Verify installed Chrome version on Windows
reg query "HKLM\Software\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv

# Verify installed Chrome version on Linux
google-chrome --version

# Verify installed Chrome version on macOS
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --version