CVE-2026-121252 in Chrome
Summary
by MITRE • 11/03/2026
Incorrect authorization in Core in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to bypass web origin policy via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified as an incorrect authorization flaw within the core components of Google Chrome, specifically affecting versions prior to 157.0.8103.38, represents a significant breach in web origin policy enforcement mechanisms. This issue stems from a logic error or insufficient validation checks during the processing of cross-origin requests, allowing a remote attacker to circumvent standard browser security boundaries. The Chromium project has classified this vulnerability with a low severity rating, indicating that while the flaw is exploitable under specific conditions, it may require user interaction or precise crafting of attack vectors to achieve successful exploitation.
At its technical core, this vulnerability exploits weaknesses in how Chrome handles origin checks for resources loaded from different domains. Web browsers rely on strict same-origin policies to prevent malicious scripts running on one site from accessing sensitive data associated with another site. In this instance, the flaw allows a crafted HTML page hosted by an attacker to trick the browser into treating content as if it originated from a trusted source or bypasses restrictions that should have blocked such access. This typically involves manipulating headers, cookies, or local storage mechanisms where authorization tokens are not correctly validated against the requesting origin.
The operational impact of this vulnerability centers on potential data exfiltration and session hijacking scenarios. An attacker could use this flaw to read sensitive information stored in cross-origin resources, such as private user data from a banking site accessed via an iframe or through AJAX requests initiated by malicious scripts. Although classified as low severity, the ability to bypass origin policies undermines the fundamental trust model of web applications. Users visiting compromised websites may inadvertently expose their credentials, personal identifiable information, or session tokens without explicit consent or awareness, leading to privacy violations and potential account compromise.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, where these authorization checks have been corrected by the Chromium security team. For organizations managing large fleets of devices, deploying automated patch management systems ensures timely application of this fix across all endpoints. Additionally, implementing Content Security Policy headers can provide an additional layer of defense by restricting which sources are allowed to load resources and execute scripts, thereby reducing the attack surface even if browser-level protections fail.
This vulnerability aligns with CWE-269, Improper Privilege Assignment, as it involves a failure in enforcing access controls correctly within the application logic. From a tactical perspective related to the MITRE ATT&CK framework, this flaw facilitates techniques associated with Collection and Credential Access, specifically those involving browser-based data theft or session hijacking via cross-site scripting variants that exploit origin policy bypasses. Security teams should monitor for indicators of exploitation targeting older Chrome versions and prioritize patching efforts to maintain robust web security postures against such logic-based attacks.