CVE-2026-2648: Google Chrome Buffer Overflow Vulnerability

CVE-2026-2648 Overview

A heap buffer overflow vulnerability has been identified in PDFium, the PDF rendering engine used by Google Chrome. This vulnerability exists in Chrome versions prior to 145.0.7632.109 and allows a remote attacker to perform an out-of-bounds memory write via a specially crafted PDF file. The vulnerability is classified as a Heap Overflow (CWE-122) and can be exploited remotely over the network when a user opens a malicious PDF document.

Critical Impact

Successful exploitation of this heap buffer overflow could allow attackers to execute arbitrary code within the context of the browser process, potentially leading to complete system compromise through malicious PDF files.

Affected Products

• Google Chrome versions prior to 145.0.7632.109
• Chromium-based browsers using vulnerable PDFium components
• Any application embedding the affected PDFium library

Discovery Timeline

• 2026-02-18 - CVE-2026-2648 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-2648

Vulnerability Analysis

This vulnerability stems from improper bounds checking in PDFium's PDF parsing functionality. When processing a maliciously crafted PDF file, the affected code fails to properly validate the size of data being written to a heap-allocated buffer. This allows an attacker to write data beyond the allocated buffer boundaries, corrupting adjacent memory regions.

The heap buffer overflow can be triggered when PDFium processes specific PDF structures or embedded objects that contain unexpected or malformed data. Since PDF files can contain complex nested structures, streams, and font definitions, there are multiple potential attack surfaces within the rendering engine.

Root Cause

The root cause is a heap-based buffer overflow (CWE-122) in the PDFium component. This occurs when the code allocates a heap buffer of insufficient size to hold incoming data, or when length calculations are performed incorrectly before memory operations. The vulnerability allows writing beyond the bounds of the allocated heap memory, which can corrupt heap metadata, adjacent objects, or function pointers stored in memory.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker can exploit this vulnerability by:

1. Crafting a malicious PDF file containing specially structured data designed to trigger the overflow
2. Distributing the malicious PDF via email attachments, malicious websites, or file-sharing services
3. Convincing a victim to open the PDF in Google Chrome or a Chromium-based browser
4. Upon rendering the PDF, the heap overflow is triggered, allowing arbitrary memory writes

The vulnerability can potentially be chained with other techniques to achieve code execution, bypass browser sandboxing, or pivot to further attacks on the underlying system. Technical details of the vulnerability can be found in the Chromium Issue Tracker #477033835.

Detection Methods for CVE-2026-2648

Indicators of Compromise

• Unusual Chrome browser crashes when opening PDF files
• Detection of malformed or suspicious PDF files with anomalous object structures
• Memory corruption errors or unexpected browser process termination
• Evidence of heap spray patterns in browser memory

Detection Strategies

• Deploy endpoint detection solutions to monitor for suspicious PDF file access patterns
• Implement browser crash monitoring and analysis for heap corruption signatures
• Use sandboxed PDF analysis tools to pre-scan attachments and downloads
• Monitor for network traffic patterns consistent with exploit kit distribution

Monitoring Recommendations

• Enable enhanced crash reporting in Chrome enterprise deployments
• Monitor endpoint telemetry for Chrome renderer process anomalies
• Implement PDF file scanning at email gateways and web proxies
• Track Chrome version compliance across the organization to identify unpatched systems

How to Mitigate CVE-2026-2648

Immediate Actions Required

• Update Google Chrome to version 145.0.7632.109 or later immediately
• Enable automatic updates for all Chrome installations
• Consider temporarily restricting PDF downloads from untrusted sources
• Educate users about the risks of opening PDF files from unknown senders

Patch Information

Google has released Chrome version 145.0.7632.109 which addresses this vulnerability. The security update includes fixes for the heap buffer overflow in PDFium. Organizations should prioritize deployment of this update across all managed endpoints. Details about the patch can be found in the Google Chrome Desktop Update announcement.

Workarounds

• Disable the built-in Chrome PDF viewer and use an alternative PDF reader
• Configure Chrome to download PDFs rather than open them directly in the browser
• Implement strict content security policies to block PDF downloads from untrusted domains
• Use browser isolation solutions to render untrusted content in isolated environments

# Configuration example - Disable Chrome PDF Viewer via Group Policy
# Chrome Enterprise Policy: AlwaysOpenPdfExternally
# Set to true to download PDFs instead of opening in Chrome

# Windows Registry approach:
reg add "HKLM\SOFTWARE\Policies\Google\Chrome" /v AlwaysOpenPdfExternally /t REG_DWORD /d 1 /f

# Verify Chrome version meets minimum requirements:
google-chrome --version
# Expected output: Google Chrome 145.0.7632.109 or higher