Description

Observable discrepancy in Autofill in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to obtain sensitive information via a crafted HTML page. (Chromium security severity: Medium)

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.3",
  "pubDate": "2026-08-25T21:17:58.917Z",
  "pubdate": "2026-08-25T21:17:58.917Z",
  "executiveSummary": "This vulnerability is an information disclosure flaw identified in the Autofill component of Google Chrome prior to version 152.0.7977.65. The issue stems from an observable discrepancy in how the browser handles autofill data, which can be leveraged by a remote attacker to exfiltrate sensitive user information.\nThe vulnerability allows unauthorized access to data that the user assumes is protected by the browser's form-filling security model. By hosting a maliciously crafted HTML page, an attacker can trigger the browser to reveal sensitive details, such as personally identifiable information (PII) or stored form data, without explicit user interaction or authorization.\nImpacted users include those running versions of Google Chrome earlier than 152.0.7977.65. The risk is considered Medium, as it requires the user to visit an attacker-controlled web page. However, given the ubiquity of browser-based autofill, the exploit poses significant privacy risks, as it bypasses the expected isolation boundaries of the browser’s input-filling mechanisms.\nNo authentication or elevated privileges are required for exploitation, as the flaw resides within the browser's core processing of form elements. Exploitation relies on the attacker's ability to manipulate DOM structures or state conditions in a way that forces the Autofill engine to reveal restricted context.",
  "technicalDetails": "The root cause of this vulnerability lies in an observable side-channel or logic error within the Chromium Autofill subsystem. Specifically, the browser's mechanisms for detecting form fields and suggesting pre-filled data exhibit behaviors that vary based on the underlying state of the user's stored profile. This allows a remote attacker to infer or extract sensitive form data through timing-based analysis or visual/DOM-state discrepancies.\nThe attack flow initiates when a user navigates to a specifically crafted HTML page hosted by an attacker. This page contains form inputs designed to trigger the browser's Autofill heuristics. By injecting custom scripts and observing the browser's response to these input fields—such as how the Autofill mechanism populates fields, or how it responds to programmatic focus and input events—an attacker can gain access to the data that is being injected.\nThe exploitation method leverages the fact that the Autofill engine may populate fields in a way that is observable via the Document Object Model (DOM). By monitoring attribute changes, form value updates, or state-related events triggered by the browser's auto-completion logic, the attacker can extract data from the browser’s autofill profile (e.g., names, addresses, or other sensitive details). The vulnerability essentially breaks the expectation that form fields remain protected until a clear user intent to fill them is expressed.\nAffected versions include all Google Chrome releases prior to 152.0.7977.65. The component responsible is the Chromium Autofill framework, which is responsible for managing the interaction between web-page form inputs and the user's saved data store. There are no authentication requirements to perform this attack, as the disclosure occurs within the scope of a standard web page rendering process.\nThe post-exploitation impact is limited to the information that the browser is configured to autofill. Because this information often includes PII, the successful execution of this attack allows for targeted profiling of users. The browser, in this scenario, effectively leaks information into the attacker's execution context, violating the security boundary between the user's sensitive data store and the untrusted web content currently being rendered."
}