CVE-2023-5474: Google Chrome Buffer Overflow Vulnerability

CVE-2023-5474 Overview

CVE-2023-5474 is a heap buffer overflow vulnerability in the PDF component of Google Chrome versions prior to 118.0.5993.70. A remote attacker can exploit this flaw by convincing a user to open a crafted PDF file, potentially triggering heap corruption. The weakness is classified under CWE-787 (Out-of-bounds Write) and affects Chrome on all desktop platforms, as well as Chromium-based packages distributed by Debian and Gentoo.

Critical Impact
Successful exploitation can lead to arbitrary code execution within the Chrome renderer process, enabling sandbox-stage attacks and full compromise of confidentiality, integrity, and availability on the affected host.

Affected Products

Google Chrome versions prior to 118.0.5993.70
Debian Linux 11 (Bullseye) and 12 (Bookworm) Chromium packages
Gentoo Linux Chromium and derivative browser packages

Discovery Timeline

2023-10-11 - CVE-2023-5474 published to the National Vulnerability Database
2023-10-10 - Google releases Chrome 118.0.5993.70 stable channel update addressing the issue
2025-05-01 - Last updated in NVD database

Technical Details for CVE-2023-5474

Vulnerability Analysis

The vulnerability resides in Chrome's PDF rendering engine, which is built on the PDFium library. Parsing a maliciously crafted PDF causes a heap buffer overflow during object processing. The flaw permits an out-of-bounds write into adjacent heap memory, corrupting structures that the renderer relies on for control flow. Attackers can leverage the corruption to influence allocator metadata or function pointers, leading to arbitrary code execution inside the renderer.

Exploitation requires user interaction. The victim must open or be redirected to a page that loads the crafted PDF. Because Chrome auto-renders PDFs inline, simply navigating to an attacker-controlled URL is sufficient to trigger the vulnerable code path. Combined with a sandbox escape, this primitive can yield full system compromise.

Root Cause

The underlying defect is an improper bounds check during PDF object parsing within PDFium. Insufficient validation of size or index values allows write operations to extend past the bounds of an allocated heap buffer, classified as [CWE-787] Out-of-bounds Write. The specific function is detailed in the upstream Chromium bug tracker entry referenced below.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker hosts a crafted PDF on a web page or delivers it via email or messaging platform. When the victim opens the file in Chrome, the embedded PDF viewer parses the malicious objects and triggers the heap overflow. No authentication is required, and the attack succeeds against default browser configurations. See the Chrome Bug Report #1483194 for technical details, noting that access remains restricted under Google's coordinated disclosure policy.

Detection Methods for CVE-2023-5474

Indicators of Compromise

Chrome renderer process crashes (chrome.exe or chrome on Linux) with heap corruption signatures shortly after PDF rendering activity
Unexpected child processes spawned from a Chrome renderer following PDF interaction
Inbound PDF files from untrusted domains containing malformed cross-reference tables or object streams
Outbound network connections from Chrome renderer processes to unfamiliar command-and-control infrastructure

Detection Strategies

Inventory Chrome installations across the fleet and flag versions below 118.0.5993.70 for remediation
Inspect web proxy and email gateway logs for PDF deliveries from low-reputation domains, especially those bypassing standard content filters
Correlate browser crash telemetry with PDF download events to identify potential exploitation attempts

Monitoring Recommendations

Monitor endpoint EDR telemetry for anomalous process trees originating from Chrome renderer processes
Track PDF file downloads and subsequent renderer behavior, including memory allocation anomalies and code execution patterns
Alert on Chrome processes loading unexpected modules or writing executables to disk following PDF interaction

How to Mitigate CVE-2023-5474

Immediate Actions Required

Update Google Chrome to version 118.0.5993.70 or later on all desktop platforms (Windows, macOS, Linux)
Apply Debian security update DSA-5526 for Chromium packages on Debian 11 and 12
Apply Gentoo GLSA advisories 202311-11, 202312-07, and 202401-34 where applicable
Restart all Chrome instances after patching to ensure the new binaries are loaded

Patch Information

Google released the fix in the Chrome stable channel update on October 10, 2023, as documented in the Google Chrome Update Bulletin. Downstream distributions issued their own packages: the Debian DSA-5526 Security Announcement covers Debian Chromium builds, and Gentoo published multiple GLSA advisories covering Chromium and dependent browsers.

Workarounds

Disable the built-in Chrome PDF viewer via enterprise policy AlwaysOpenPdfExternally until patching is complete
Configure web and email gateways to scan or block PDF attachments from untrusted senders
Restrict Chrome usage to managed profiles where automatic updates are enforced through enterprise policy

bash

# Enterprise policy to disable inline PDF rendering on Windows (registry)
reg add "HKLM\Software\Policies\Google\Chrome" /v AlwaysOpenPdfExternally /t REG_DWORD /d 1 /f

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

# Debian: apply security update
sudo apt-get update && sudo apt-get install --only-upgrade chromium