CVE-2026-4453 is an integer overflow vulnerability found in the Dawn component of Google Chrome on Mac platforms, affecting versions prior to 146.0.7680.153. The flaw arises when the browser improperly handles integer values during processing of certain HTML content, leading to an overflow condition. This overflow can be exploited by a remote attacker who crafts a malicious HTML page designed to trigger the vulnerability. Successful exploitation allows the attacker to bypass same-origin policy restrictions and leak cross-origin data, compromising the confidentiality of information from other web origins. The vulnerability does not require prior authentication but does require the victim to visit the malicious page, implying user interaction is necessary. Although no public exploits have been reported, the Chromium security team has classified this vulnerability as high severity due to the potential for sensitive data exposure. The vulnerability is specific to the Mac version of Chrome and is addressed in the security update released in version 146.0.7680.153. The lack of a CVSS score necessitates an independent severity assessment based on the impact on confidentiality, ease of exploitation, and scope of affected systems.

The primary impact of CVE-2026-4453 is the unauthorized disclosure of sensitive information across web origins, violating the same-origin policy that underpins web security. This can lead to leakage of confidential user data such as authentication tokens, personal information, or other sensitive content accessible in the browser context. Organizations with employees or users on Mac systems running vulnerable Chrome versions are at risk of data breaches and privacy violations. The attack vector requires user interaction, which may limit mass exploitation but targeted spear-phishing or malicious web campaigns could be effective. The vulnerability undermines trust in web isolation mechanisms and could be leveraged as part of more complex attack chains. Although availability and integrity are not directly impacted, the confidentiality breach alone can have serious consequences including regulatory penalties, reputational damage, and potential lateral movement within corporate networks if sensitive credentials are exposed.

To mitigate CVE-2026-4453, organizations should immediately update all Mac-based Chrome browsers to version 146.0.7680.153 or later, where the vulnerability is patched. Enterprises should enforce automated update policies and verify compliance through endpoint management tools. Additionally, implement web filtering and content security policies to restrict access to untrusted or suspicious websites that could host malicious HTML content. Security awareness training should emphasize the risks of interacting with unknown links or web pages. Network monitoring should be enhanced to detect unusual outbound data flows that may indicate data exfiltration attempts. Consider deploying browser isolation technologies for high-risk users to contain potential exploitation. Finally, maintain an incident response plan that includes steps for handling potential data leakage incidents stemming from browser vulnerabilities.