CVE-2026-121184 in Chrome
Summary
by MITRE • 11/03/2026
Out of bounds read in Media in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to potentially execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as an out-of-bounds read within the Media component of Google Chrome represents a significant memory safety flaw that was present in versions prior to 157.0.8103.38. This type of error typically occurs when software attempts to access data at a memory location beyond the intended boundary, often due to improper validation of input parameters or incorrect calculation of array indices during media processing operations. In the context of web browsers, such flaws are particularly critical because they reside within components that handle complex multimedia streams and codecs, which are frequently subjected to untrusted inputs from remote websites. The Chromium security team classified this issue with a medium severity rating, reflecting its potential for exploitation under specific conditions while acknowledging the mitigating factors provided by Chrome's sandboxing architecture.
From a technical perspective, an out-of-bounds read allows an attacker to leak sensitive information stored in adjacent memory locations that were not intended to be accessed. While modern browser sandboxes are designed to restrict the impact of such vulnerabilities by limiting what code executed within them can do with leaked data, the primary risk remains the potential for arbitrary code execution if the vulnerability is chained with other weaknesses or if specific conditions allow for information disclosure that aids in bypassing security controls like ASLR or DEP. The attack vector involves a crafted HTML page containing malicious JavaScript and media elements designed to trigger the flawed memory access routine within the browser's rendering engine. When a user visits this page, the browser attempts to process the malformed media data, leading to the out-of-bounds read condition.
The operational impact of this vulnerability is substantial for end-users who rely on Chrome for browsing content that includes embedded audio or video files. An attacker could potentially exploit this flaw by hosting malicious web content and tricking a user into visiting it through social engineering techniques such as phishing emails, compromised websites, or drive-by downloads. If successful, the exploitation could lead to unauthorized access to browser memory contents, which may include cookies, session tokens, passwords stored in autofill, or other sensitive data residing in the process space of the renderer. Although the sandbox limits direct system-level control, information disclosure can serve as a stepping stone for more sophisticated attacks that aim to escape the sandbox environment entirely.
This vulnerability aligns with CWE-125, which describes Out-of-bounds Read, and is relevant to MITRE ATT&CK techniques related to Initial Access via Spearphishing Link or Drive-by Compromise, specifically under Tactic TA0001 for Reconnaissance if used primarily for data exfiltration. To mitigate the risks associated with this vulnerability, users must ensure that their Google Chrome installation is updated to version 157.0.8103.38 or later immediately upon availability. Organizations should enforce automated update policies across all endpoints to minimize the window of exposure. Additionally, security teams can implement browser hardening techniques such as disabling unnecessary plugins and restricting JavaScript execution on untrusted domains where feasible, although these measures are supplementary to patching the underlying software defect. Regular monitoring for new CVEs affecting widely used browsers is essential to maintain a robust defense posture against web-based attack vectors.