Throughout 2025, Google addressed a significant wave of actively exploited zero-day vulnerabilities affecting its Chrome browser, patching a total of eight critical flaws that threatened billions of users worldwide.
These vulnerabilities, all classified as high severity with CVSS scores averaging 8.5, underscore the persistent targeting of the world’s most popular web browser by sophisticated threat actors, including state-sponsored groups and commercial surveillance vendors.
The vulnerabilities spanned critical components, including the V8 JavaScript engine, sandbox protection mechanisms, and graphics rendering layers, with all eight added to CISA’s Known Exploited Vulnerabilities catalog, mandating immediate remediation for federal agencies and serving as urgent warnings for organizations globally.
2025 Chrome Zero-Day Landscape
The eight zero-day vulnerabilities patched in 2025 concentrated heavily on Chrome’s V8 JavaScript and WebAssembly engine, which accounted for four of the eight flaws, representing 50% of all actively exploited vulnerabilities during this period.
This concentration reflects the strategic importance of V8 as an attack vector, given its role in executing JavaScript code across virtually all modern web applications. The V8 engine processes millions of code executions daily, making any vulnerability within this component immediately exploitable at a massive scale.
The remaining vulnerabilities targeted equally critical components: two affected the ANGLE (Almost Native Graphics Layer Engine) graphics abstraction layer used for GPU operations, one exploited the Mojo inter-process communication framework on Windows, and one leveraged insufficient policy enforcement in Chrome’s Loader component.
This distribution reveals attackers’ sophisticated understanding of Chrome’s multi-layered architecture and their ability to identify weaknesses across different security boundaries.
Google’s Threat Analysis Group (TAG) played a pivotal role in discovering and reporting six of the eight vulnerabilities, demonstrating the company’s internal security research capabilities and its focus on tracking nation-state actors and commercial surveillance vendors.
External contributions came from Kaspersky’s Global Research and Analysis Team, which discovered the first zero-day of 2025, and Apple’s Security Engineering and Architecture team, which co-reported the final vulnerability of the year.
The temporal distribution of these vulnerabilities reveals a consistent threat throughout 2025, with patches deployed across eight separate months from March through December. Unlike typical vulnerability disclosure patterns that often cluster around major releases or security audits, the steady stream of zero-day discoveries suggests ongoing active exploitation attempts by threat actors throughout the year.
March marked the beginning with CVE-2025-2783, a Mojo sandbox escape vulnerability exploited in Operation ForumTroll, a sophisticated espionage campaign targeting Russian government organizations and media outlets.
May saw CVE-2025-4664, an account-hijacking vulnerability in Chrome’s Loader component that enabled cross-origin data leakage. In June, two critical V8 engine flaws, CVE-2025-5419 and CVE-2025-6554, were actively exploited via type confusion and out-of-bounds memory access.
July introduced CVE-2025-6558, which exploited insufficient input validation in ANGLE and GPU components to achieve sandbox escape. September saw CVE-2025-10585, another V8 type confusion vulnerability that allowed heap corruption via crafted HTML pages.
November brought CVE-2025-13223, the seventh zero-day, again targeting V8 with type confusion techniques linked to espionage operations. December closed the year with CVE-2025-14174, an out-of-bounds memory access vulnerability in ANGLE specifically affecting macOS users.
This consistent pattern of exploitation demonstrates that Chrome remains a high-value target for sophisticated adversaries despite Google’s substantial investments in security hardening, including technologies such as MiraclePtr for memory-corruption prevention and enhanced sandbox isolation.
Technical Analysis of Exploitation Methods
V8 Type Confusion Vulnerabilities
Type confusion vulnerabilities dominated the 2025 Chrome zero-day landscape, accounting for three of the eight actively exploited flaws—CVE-2025-6554, CVE-2025-10585, and CVE-2025-13223.
These vulnerabilities exploit a fundamental characteristic of JavaScript’s dynamic type system and V8’s optimization strategies. Type confusion occurs when the V8 engine misinterprets a memory location as containing a different object type than actually stored, leading to memory corruption that attackers can leverage for arbitrary code execution.
The V8 engine employs sophisticated just-in-time (JIT) compilation to achieve high performance, making assumptions about object types during optimization.
The technical sophistication required to exploit V8 type confusion vulnerabilities is substantial. Attackers must understand V8’s internal object representation, including Hidden Classes (Maps) that describe object layouts, in-object properties, and the JavaScript object structure within V8’s heap.
Successful exploitation typically involves heap spraying techniques to control memory layout, manipulating object prototypes to create type confusion conditions, and leveraging the corrupted memory state to achieve read/write primitives that enable code execution.
CVE-2025-10585, discovered by Google TAG on September 16, 2025, exemplifies this attack pattern. The vulnerability allowed remote attackers to exploit heap corruption through type confusion in V8, with Google confirming active in-the-wild exploitation. The flaw required victims to visit a malicious website containing crafted JavaScript, demonstrating the low barrier to exploitation once the vulnerability is weaponized.
Sandbox Escape Mechanisms
Two of the eight zero-day vulnerabilities, CVE-2025-2783 and CVE-2025-6558, specifically enabled sandbox escape, representing the most severe class of browser vulnerabilities by allowing attackers to break free from Chrome’s isolation mechanisms and access the underlying operating system.
CVE-2025-2783, discovered by Kaspersky in March 2025, targeted the Mojo inter-process communication framework on Windows platforms. Mojo serves as Chrome’s IPC mechanism, enabling communication between the browser’s isolated renderer processes and the privileged browser kernel process.
The vulnerability stemmed from an incorrect handle being provided in unspecified circumstances, allowing remote attackers to perform sandbox escape via a malicious file.
When CVE-2025-2783 was exploited in Operation ForumTroll, attackers chained it with a separate renderer exploit to achieve full system compromise.
The attack began with phishing emails containing links to a malicious website that exploited a renderer vulnerability, followed by leveraging CVE-2025-2783 to escape the sandbox and deploy LeetAgent spyware on victims’ systems.
CVE-2025-6558, discovered by Google TAG in July 2025, exploited insufficient validation of untrusted input in Chrome’s ANGLE component and GPU subsystem. ANGLE serves as a translation layer between Chrome’s rendering engine and device-specific graphics drivers, handling OpenGL ES API calls and converting them to native graphics APIs like Metal on macOS or Direct3D on Windows.
Memory Corruption Exploitation
Three vulnerabilities, CVE-2025-5419, CVE-2025-6558, and CVE-2025-14174, centered on out-of-bounds memory access, a class of memory corruption bugs that enable attackers to read or write memory outside allocated buffer boundaries.
These vulnerabilities can lead to information disclosure through out-of-bounds reads, allowing attackers to leak sensitive data from adjacent memory regions, or to arbitrary code execution through out-of-bounds writes that corrupt critical data structures.
CVE-2025-5419, patched in June 2025, involved out-of-bounds read and write conditions in the V8 engine that allowed remote attackers to trigger heap corruption via crafted HTML pages.
CVE-2025-14174, discovered in December 2025, specifically affected Chrome’s ANGLE implementation on macOS, involving improper memory handling that allowed memory access out of bounds during the rendering of crafted HTML pages.
The technical exploitation of out-of-bounds memory vulnerabilities typically involves carefully controlling heap layout through techniques like heap spraying, crafting input that triggers the out-of-bounds access at a predictable memory location, and leveraging the ability to read or write arbitrary memory to construct exploitation primitives.
Mitigations
The eight Chrome zero-day vulnerabilities actively exploited throughout 2025 represent a sophisticated and persistent threat landscape targeting the world’s most widely used web browser.
The concentration of vulnerabilities in core components like the V8 JavaScript engine and ANGLE graphics layer, combined with the involvement of nation-state threat actors and commercial surveillance vendors, underscores Chrome’s status as a critical attack surface in modern cyber operations.
Beyond immediate patching, organizations should implement comprehensive browser security strategies. Browser isolation technologies that execute web content in remote, disposable environments can effectively sandbox potential threats away from endpoints, providing protection even against unknown zero-days.
Network-based security controls, including next-generation firewalls, intrusion detection/prevention systems, and web application firewalls, can identify and block exploitation attempts based on behavioral indicators.
Google’s rapid response capabilities and multi-layered security architecture have proven effective in limiting exposure windows and preventing widespread compromise, yet the steady pace of exploitation throughout the year demonstrates that determined adversaries continue to find and weaponize Chrome vulnerabilities.
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