CVE-2026-103623 in Chrome
Summary
by MITRE • 10/02/2026
Use after free in MediaStream in Google Chrome prior to 154.0.8037.97 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 • 10/02/2026
The vulnerability identified as a use-after-free condition within the MediaStream component of Google Chrome prior to version 154.0.8037.97 represents a critical memory safety flaw that compromises the integrity and confidentiality of user data. This specific defect arises when the browser's media handling subsystem fails to properly manage the lifecycle of objects associated with audio or video streams, leading to a scenario where previously freed memory is accessed by subsequent operations. In modern web browsers, such as Chrome, complex multimedia functionalities are implemented through intricate interactions between JavaScript engines and native C++ codebases. When an attacker crafts a malicious HTML page that triggers this specific sequence of events, they can exploit the dangling pointer resulting from the premature deallocation of media stream resources. This exploitation vector allows for arbitrary code execution within the browser's sandboxed environment, which is designed to isolate web content from the underlying operating system and user files.
From a technical perspective, use-after-free vulnerabilities are among the most dangerous classes of memory corruption errors because they provide attackers with significant control over program flow and data manipulation. The MediaStream API in Chromium handles real-time communication and media capture, involving dynamic allocation and deallocation of structures that track stream states, tracks, and associated buffers. If an application accesses a pointer after the object it points to has been freed, the memory may have already been reassigned to another purpose or marked as available for reuse by the heap allocator. By carefully crafting input data within the malicious HTML page, an attacker can influence what gets written into that reclaimed memory space before it is accessed again. This technique enables the injection of shellcode or the modification of function pointers, ultimately leading to arbitrary code execution with the privileges granted to the browser process.
The operational impact of this vulnerability is severe due to its remote exploitability and high severity rating assigned by Chromium security teams. A successful exploitation does not require physical access or user interaction beyond visiting a compromised website, making it suitable for drive-by download attacks. Although Chrome employs multiple layers of defense such as sandboxing, data execution prevention, and address space layout randomization, these mitigations are designed to raise the bar for attackers rather than provide absolute immunity against sophisticated memory corruption bugs. The ability to execute arbitrary code inside the sandbox allows an attacker to potentially escape the browser's isolation boundaries if combined with other vulnerabilities or through advanced exploitation techniques that target sandbox escapes. This could result in full system compromise, including theft of sensitive information such as credentials, cookies, and personal data stored locally by the browser.
This vulnerability aligns closely with Common Weakness Enumeration identifier CWE-416, which describes use after free errors where a pointer is used after it has been freed or deallocated. The exploitation methodology typically follows patterns observed in ATT&CK technique T1203, specifically the execution of exploits for client-side software vulnerabilities. Attackers often distribute such malicious pages through phishing campaigns, compromised websites, or ad networks to maximize reach and success rates. The high severity classification reflects the potential for widespread impact across a large user base running outdated versions of Chrome, emphasizing the urgency of patching efforts within enterprise environments and individual systems alike.
Mitigation strategies primarily focus on timely software updates and robust security hygiene practices. Users must ensure that Google Chrome is updated to version 154.0.8037.97 or later, where this memory management flaw has been corrected by the Chromium development team through rigorous code review and automated fuzzing tests designed to detect such lifecycle errors early in the software development cycle. For organizations, implementing strict update policies that automatically deploy security patches is essential to reduce the window of exposure. Additionally, deploying endpoint detection and response solutions can help identify suspicious behavior patterns associated with exploit attempts, such as unusual memory access violations or unexpected process spawns originating from browser processes. Enabling sandboxing features and restricting permissions for media APIs on untrusted sites further reduces the attack surface available to potential adversaries seeking to leverage this vulnerability.