CVE-2026-121188 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in PerformanceAPIs in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as a use-after-free flaw within the PerformanceAPIs component of Google Chrome prior to version 157.0.8103.38 represents a critical memory management error that compromises the integrity and confidentiality of user data. This specific class of vulnerabilities occurs when a program continues to use a pointer after it has been freed, leading to undefined behavior that can be exploited by malicious actors. In this instance, the flaw resides in how Chrome handles performance metrics and timing data exposed through web APIs, which are frequently accessed by modern web applications for analytics and optimization purposes. The presence of such an error indicates a lapse in reference counting or memory lifecycle management within the browser engine's core processing logic.
From a technical perspective, use-after-free vulnerabilities arise when memory allocated to store specific objects is deallocated while references to that memory remain active. When the attacker crafts a malicious HTML page designed to trigger this condition, they can manipulate the freed memory region before it is reallocated for another purpose. By carefully controlling the content written into this reclaimed memory space, an attacker can overwrite critical data structures or function pointers within the browser's sandboxed environment. This manipulation allows for arbitrary code execution, effectively bypassing Chrome’s robust security boundaries and granting the malicious script elevated privileges equivalent to those of the local user running the browser.
The operational impact of this vulnerability is severe due to its remote exploitability via a simple crafted web page. Users visiting compromised or maliciously designed websites could trigger the flaw without any additional interaction, such as clicking buttons or downloading files. Once arbitrary code execution is achieved within the sandbox, an attacker can potentially escalate privileges to escape the browser container entirely. This escape capability poses significant risks including data theft, installation of persistent malware, and lateral movement across networked systems if the user has access to sensitive internal resources. The high severity rating assigned by Chromium reflects the ease with which this flaw can be leveraged in real-world attack scenarios against unpatched installations.
Mitigation strategies primarily involve immediate software updates to ensure all instances of Google Chrome are upgraded to version 157.0.8103.38 or later, where these memory management issues have been addressed through rigorous code reviews and automated testing protocols. Organizations should enforce strict update policies across all endpoints to minimize the window of exposure. Additionally, deploying browser isolation technologies or sandboxing solutions can provide an additional layer of defense by limiting the potential impact even if a vulnerability is successfully exploited. Security teams should also monitor for indicators of compromise associated with drive-by download attacks targeting this specific flaw and ensure that web content security policies are configured to restrict execution of untrusted scripts where feasible.
This incident aligns with Common Weakness Enumeration identifier CWE-416, which describes use after free errors as a significant category of memory safety issues prevalent in C and C++ based software like Chromium browsers. Furthermore, the exploitation technique maps closely to MITRE ATT&CK techniques related to initial access through browser exploits and subsequent privilege escalation via sandbox escape mechanisms. Understanding these mappings helps security professionals contextualize the threat within broader attack frameworks and prioritize remediation efforts accordingly. Continuous monitoring of vulnerability databases and adherence to vendor patch cycles remain essential practices for maintaining a secure browsing environment against such sophisticated memory corruption attacks.