CVE-2026-87590 in Chrome
Summary
by MITRE • 09/09/2026
Improper input validation in Passwords in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to potentially leak sensitive information via crafted network traffic. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an improper input validation flaw within the password handling mechanisms of Google Chrome versions prior to 153.0.8010.36 represents a significant risk to user data confidentiality. This issue stems from insufficient sanitization or boundary checking when processing network traffic related to credential storage and retrieval operations. In modern web browsers, passwords are often managed through specialized subsystems that interact with both local storage backends and remote authentication services via HTTPS connections. When the browser receives crafted network packets containing malformed or unexpectedly structured data intended for password-related endpoints, it fails to properly validate the input before processing. This lack of rigorous validation allows an attacker who can intercept or manipulate network traffic in a man-in-the-middle scenario to inject malicious payloads into these communication channels. The severity is classified as medium by Chromium security standards because while direct code execution is not implied, the potential for information disclosure poses a serious threat to user privacy and account security.
From a technical perspective, this flaw likely involves edge cases where specific characters or encoding schemes are mishandled during the parsing of authentication headers or cookie data associated with saved passwords. If an attacker can craft network traffic that exploits these parsing inconsistencies, they may trigger behaviors such as buffer over-reads or logic errors that result in the browser exposing sensitive internal states to external observers. This could manifest as the leakage of password hashes, session tokens, or other credentials stored within the browser profile. The attack vector requires the victim to be using a vulnerable version of Chrome and potentially involves social engineering or network interception techniques to deliver the crafted traffic. It is important to note that this vulnerability does not typically allow for arbitrary code execution but rather focuses on data exfiltration through improper handling of untrusted input within the password subsystem.
The operational impact of this vulnerability centers on the compromise of user credentials and session integrity. If successful, an attacker could gain unauthorized access to online accounts by harvesting sensitive information that was intended to remain confidential. This undermines the fundamental trust users place in their web browsers as secure gateways for digital identity management. The exposure of such data can lead to account takeover, financial loss, or further exploitation through credential stuffing attacks against other services where users have reused passwords. For organizations relying on Chrome for corporate browsing, this vulnerability also poses a risk to internal systems if employees use the same credentials across different platforms. The medium severity rating reflects that while the impact is significant, it requires specific conditions such as network access and user interaction with vulnerable pages or extensions to be fully exploited.
To mitigate this risk, users must upgrade Google Chrome immediately to version 153.0.8010.36 or later, where these input validation checks have been strengthened. Security teams should also enforce the use of up-to-date browsers across all endpoints and monitor for any signs of credential leakage in logs or security information and event management systems. Implementing multi-factor authentication adds a critical layer of defense that remains effective even if passwords are compromised through such vulnerabilities. Additionally, network segmentation and strict TLS enforcement can reduce the likelihood of successful man-in-the-middle attacks that deliver crafted traffic to vulnerable browser instances. This incident aligns with CWE-20 Improper Input Validation and ATT&CK technique T1539 Steal Web Session Cookie, highlighting the importance of robust input sanitization in web application security architectures.