Description

Improper input validation in Sync in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to obtain sensitive information via crafted network traffic. (Chromium security severity: Medium)

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-08-25T21:17:57.073Z",
  "pubdate": "2026-08-25T21:17:57.073Z",
  "executiveSummary": "A vulnerability categorized as improper input validation exists within the Sync component of Google Chrome.\nThis security flaw allows a remote, unauthenticated attacker to induce an information disclosure state by sending specifically crafted network traffic to a vulnerable client.\nThe vulnerability affects Google Chrome versions prior to 152.0.7977.65.\nThe primary risk implication is the unauthorized extraction of sensitive information handled by the Sync service, which could potentially expose synchronized user data, browser configurations, or session-related tokens.\nExploitation does not require prior authentication, relying instead on the victim's interaction with malicious or compromised network traffic.\nGiven the nature of Sync services, this vulnerability poses a significant risk to data privacy, as the exploitation flow bypasses standard validation logic to leak protected memory or state information via the network layer.\nThe Chromium security severity for this issue is rated as Medium, reflecting the impact of the data exposure while acknowledging the specific conditions required for the successful manipulation of incoming network streams.",
  "technicalDetails": "The root cause of this vulnerability lies in the insufficient validation of incoming network data packets within the Google Chrome Sync component. When the browser's Sync subsystem processes network traffic, it fails to adequately sanitize or verify the structure and content of incoming payloads before parsing them.\nThe attack flow initiates when a remote attacker sends specially crafted, malicious network traffic to a target Chrome instance. Because the input validation logic is flawed, the Sync component interprets this crafted data as legitimate instructions or serialized objects. This discrepancy leads to the unintended processing of payload segments that would otherwise be rejected by a strictly compliant implementation.\nUpon receiving the malicious data, the Sync component may inadvertently disclose sensitive information during the processing cycle. This happens because the inadequate validation allows the parser to access or return memory regions or internal synchronization states that are exposed to the network response stream.\nThe vulnerable component is the browser's internal Sync module, which is responsible for coordinating data across devices. The exploitation method leverages this architectural trust; the component assumes the incoming traffic adheres to the expected protocol specifications. By violating these expectations through crafted inputs, an attacker forces the application into an error-handling path or an unexpected state that leaks sensitive data via the return path of the network communication.\nThis vulnerability is classified as an improper input validation issue because the codebase fails to enforce boundary and type checks on incoming packets. There are no specific authentication or privilege requirements to trigger this flaw, as the network interface for the Sync service is exposed to accept remote traffic. The impact is significant in terms of post-exploitation, as successful information disclosure can provide an attacker with high-value data, such as cached synchronization tokens or sensitive user profile details, which may be leveraged for further attacks or account compromise.\nThe issue is addressed by updating Google Chrome to version 152.0.7977.65 or later, which incorporates stricter input sanitization routines and improved protocol validation logic to ensure that only well-formed, authorized traffic is processed by the Sync component, effectively preventing the leakage of internal data during packet parsing."
}