CVE-2026-106287 in Chrome
Summary
by MITRE • 10/06/2026
Information loss in CORS in Google Chrome prior to 155.0.8059.39 allowed a remote attacker to bypass web origin policy via crafted network traffic. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified as an information leak within the Cross-Origin Resource Sharing mechanism of Google Chrome versions prior to 155.0.8059.39 represents a subtle but significant deviation from expected browser security behavior. At its core, this flaw involves the improper handling of network traffic during cross-origin requests, which inadvertently exposes sensitive data that should remain isolated by the same-origin policy. The Cross-Origin Resource Sharing standard is designed to allow web servers to specify who can access their resources, yet when implemented incorrectly within a user agent like Chrome, it can create side channels or leakage points where an attacker might infer information about protected origins or internal network states through crafted requests and observed responses.
From a technical perspective, the flaw likely stems from how the browser processes preflight requests or handles error conditions during CORS validation. In many such scenarios, subtle differences in response headers, timing, or HTTP status codes can be exploited by an attacker to determine whether specific resources exist on a target origin or to gather metadata about internal services that are not intended for public consumption. This type of vulnerability does not typically allow for direct code execution but rather facilitates reconnaissance and data gathering, which can serve as the initial foothold in more complex attack chains involving server-side request forgery or cross-site scripting exploitation where precise knowledge of target infrastructure is required.
The operational impact of this vulnerability centers on the erosion of web origin isolation principles that protect user privacy and application integrity. By allowing a remote attacker to bypass aspects of the web origin policy through crafted network traffic, Chrome users are exposed to potential information disclosure risks. This could lead to unauthorized access to sensitive data if combined with other vulnerabilities or misconfigurations in target applications. The Chromium security team has classified this issue as low severity, indicating that while it violates security boundaries, it requires specific conditions and likely does not result in immediate critical compromise without additional exploitation steps. However, even low-severity issues can be chained together to achieve higher impact outcomes, making their remediation important for maintaining a robust defense-in-depth posture.
Mitigation strategies primarily involve updating the browser environment to version 155.0.8059.39 or later, where these CORS handling mechanisms have been corrected to strictly adhere to security standards and prevent information leakage through network traffic anomalies. Organizations should ensure that all client endpoints are patched promptly to eliminate this attack vector. Additionally, developers of web applications relying on Chrome for sensitive operations should implement strict Content Security Policy directives and validate server-side responses rigorously to minimize reliance solely on browser-enforced protections. Monitoring logs for unusual cross-origin request patterns can also help detect potential exploitation attempts in real-time environments where patching might be delayed due to operational constraints.
This vulnerability aligns with CWE-209, which describes the generation of an error message that includes sensitive information about the environment, and CWE-359, involving exposure of private personal information through side channels. In terms of offensive security frameworks, it relates to ATT&CK technique T1078, specifically valid accounts or system discovery phases where attackers gather intelligence before launching more direct attacks. Understanding these classifications helps in contextualizing the risk within broader threat landscapes and prioritizing remediation efforts based on potential exploitation pathways rather than just severity scores alone.