CVE-2025-1918 is an out-of-bounds read vulnerability found in the PDFium library integrated within Google Chrome versions prior to 134.0.6998.35. PDFium is responsible for rendering PDF documents in the browser. This vulnerability arises when a specially crafted PDF file causes the PDFium component to read memory outside of its intended bounds, potentially exposing sensitive information or causing memory corruption. The flaw can be triggered remotely by an attacker who convinces a user to open or preview a malicious PDF document, requiring user interaction but no prior authentication or elevated privileges. The vulnerability affects the confidentiality, integrity, and availability of the browser environment, as it may lead to information disclosure, browser crashes, or potentially facilitate further exploitation such as code execution through memory corruption chains. The CVSS 3.1 base score of 8.8 reflects the ease of remote exploitation (network vector), low attack complexity, no privileges required, but requiring user interaction, and the high impact on confidentiality, integrity, and availability. Although no known exploits are reported in the wild yet, the severity and nature of the vulnerability make it a critical patching priority. The vulnerability was publicly disclosed on March 5, 2025, and Google has released version 134.0.6998.35 to address this issue. Organizations relying on Chrome for web browsing, especially those handling sensitive data or operating in high-risk environments, should prioritize updating to the patched version to mitigate potential exploitation risks.

The vulnerability poses a significant risk to organizations worldwide by potentially exposing sensitive information through out-of-bounds memory reads, which can lead to data leakage. It also threatens the integrity and availability of the browser by causing crashes or enabling further exploitation. Attackers can remotely exploit this flaw by delivering malicious PDF files, making phishing campaigns or drive-by downloads effective attack vectors. This can result in compromised user sessions, unauthorized data access, or disruption of business operations. Enterprises with high reliance on Chrome for accessing web applications, especially those in finance, healthcare, government, and critical infrastructure sectors, face elevated risks. The vulnerability's ability to impact confidentiality, integrity, and availability simultaneously amplifies its threat level, potentially leading to regulatory compliance issues and reputational damage if exploited.

1. Immediately update all Google Chrome installations to version 134.0.6998.35 or later to apply the official patch. 2. Implement network-level controls to block or quarantine suspicious PDF files, especially those received via email or downloaded from untrusted sources. 3. Employ endpoint security solutions capable of detecting and blocking malicious PDF payloads or anomalous PDF processing behaviors. 4. Educate users to avoid opening PDFs from unknown or untrusted sources and to report suspicious documents. 5. Where feasible, disable automatic PDF rendering or previewing in browsers and use dedicated PDF viewers with robust security controls. 6. Monitor security advisories and threat intelligence feeds for any emerging exploits targeting this vulnerability. 7. Conduct regular vulnerability assessments and penetration tests focusing on PDF handling components within the organization’s environment. 8. Apply principle of least privilege to browser processes and sandboxing features to limit the impact of potential exploitation.