CVE-2026-17861
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Updater in Google Chrome prior to 151.0.7922.72 allowed a local attacker to perform OS-level privilege escalation via a malicious file. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical privilege escalation flaw in Google Chrome's updater component that could be exploited by local attackers to gain elevated system privileges. The issue stems from inadequate validation of untrusted input within the updater module, creating a pathway for malicious actors to manipulate the update process and execute arbitrary code with OS-level privileges. The vulnerability affects Chrome versions prior to 151.0.7922.72 and demonstrates a fundamental failure in input sanitization that directly violates security best practices.
The technical flaw manifests when the updater component processes untrusted files without proper validation mechanisms, allowing attackers to craft malicious payloads that bypass normal security checks. This weakness can be exploited through various attack vectors including file injection, symlink manipulation, or direct file replacement techniques. The vulnerability operates at a low level within the operating system's privilege model, where the updater process runs with elevated permissions and fails to properly validate the integrity and source of files it processes. This represents a classic example of insufficient input validation that maps directly to CWE-20, which covers weaknesses related to improper input validation in software systems.
The operational impact of this vulnerability is significant as it enables local attackers who already have user-level access to escalate their privileges to system administrator or root level access. Attackers can leverage this flaw by placing malicious files in locations where the updater expects legitimate update content, causing the system to execute unauthorized code with elevated privileges. This type of attack aligns with ATT&CK technique T1068, which covers local privilege escalation through the exploitation of software vulnerabilities. The vulnerability essentially creates a backdoor path for attackers to bypass normal authentication mechanisms and gain persistent access to systems.
From a security perspective, this vulnerability highlights the critical importance of input validation in privileged components and demonstrates how seemingly minor flaws can create major security risks. The updater process represents a high-value target since it typically runs with elevated privileges and has direct access to system resources. Organizations should prioritize patching this vulnerability immediately and implement additional monitoring for suspicious file modifications in update directories. The issue also underscores the need for principle of least privilege enforcement and proper sandboxing of privileged components to limit potential damage from similar vulnerabilities in the future. Security teams must ensure that all components handling untrusted input undergo rigorous validation and sanitization processes to prevent exploitation of similar weaknesses.