CVE-2026-78956 in Chrome
Summary
by MITRE • 08/26/2026
Type confusion in V8 in Google Chrome prior to 152.0.7977.65 allowed a remote attacker leveraging social engineering to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Low)
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as a type confusion flaw within the V8 JavaScript engine, which powers Google Chrome prior to version 152.0.7977.65, represents a critical memory safety issue that undermines the integrity of the browser's execution environment. Type confusion vulnerabilities occur when an application incorrectly assumes the data type of a variable or object during runtime, leading to operations being performed on incompatible types. In the context of V8, this typically involves misinterpreting JavaScript objects as different internal structures, such as confusing a heap-allocated array with a pointer to executable code or another sensitive memory structure. This discrepancy allows an attacker who can inject and execute arbitrary JavaScript through a crafted HTML page to manipulate how the engine handles memory references, effectively bypassing standard type checks that are designed to prevent unauthorized access or modification of system resources.
From a technical perspective, this flaw exploits the complex interaction between V8's Just-In-Time (JIT) compilation mechanisms and its garbage collection subsystems. When the browser processes maliciously crafted scripts, it may allocate memory for an object but later interpret that same memory region using metadata associated with a different type. This misalignment can lead to out-of-bounds reads or writes, allowing the attacker to read sensitive information from adjacent memory locations or overwrite critical data structures such as function pointers or virtual table entries. By carefully crafting the input, an adversary can control the values written into these overwritten regions, thereby gaining the ability to redirect execution flow to arbitrary code placed in writable and executable memory segments. This mechanism is fundamental to achieving remote code execution within the constrained sandbox environment that Chrome employs to isolate web content from the host operating system.
The operational impact of this vulnerability is significant despite its classification as a low severity issue by Chromium security teams, primarily due to the high bar for exploitation success in modern browsers. While the browser implements multiple layers of defense including Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), and sandboxing, type confusion bugs remain among the most potent vectors for breaking out of these protections if exploited correctly. An attacker leveraging social engineering techniques can entice a user to visit a malicious website hosting the exploit kit containing the crafted HTML page. Upon loading this page, the V8 engine processes the malicious script, triggering the type confusion error and allowing the execution of arbitrary code with the privileges of the browser process. Although sandboxing limits the immediate damage by restricting access to critical system files or hardware interfaces, successful exploitation can still lead to data exfiltration, installation of further malware payloads within the user's profile directory, or use of the compromised machine as part of a botnet for distributed attacks.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-843, which refers to Accessing Memory Location using Wrong Pointer Type, and is closely related to CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer. In terms of offensive security frameworks such as MITRE ATT&CK, this exploit technique falls under Tactic TA0002 Execution and specifically relates to techniques like T1059 Command and Scripting Interpreter or potentially T1203 Exploitation for Client Execution if it leads to further payload delivery. The reliance on social engineering highlights the importance of user awareness alongside technical controls, as no amount of sandbox hardening can fully mitigate risks posed by users who are tricked into visiting malicious sites that contain sophisticated exploit code targeting known vulnerabilities in their software stack.
Mitigation strategies for this vulnerability primarily involve ensuring that all instances of Google Chrome and its underlying V8 engine components are updated to version 152.0.7977.65 or later, where the type confusion logic has been corrected by developers through rigorous code review and fuzzing efforts. Organizations should enforce automated patch management policies to minimize the window of exposure for end-user devices. Additionally, deploying browser hardening solutions such as Google Chrome Enterprise Bundle features like Site Isolation can help contain potential breaches even if a vulnerability is successfully exploited, limiting the attacker's ability to access cross-origin data or escape the sandbox effectively. Security awareness training remains crucial in reducing the success rate of social engineering campaigns that attempt to deliver these exploits to unsuspecting users, complementing the technical safeguards provided by updated software versions.