CVE-2026-118309 in Chrome
Summary
by MITRE • 10/28/2026
Improper input validation in UI in Google Chrome on on Android prior to 156.0.8078.73 allowed a remote attacker to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified as an improper input validation flaw within the user interface of Google Chrome on Android, specifically in versions prior to 156.0.8078.73, represents a significant breach in browser security boundaries. This issue stems from insufficient sanitization and type checking mechanisms when processing inputs that interact with critical rendering or scripting engines. The core technical flaw lies in the failure of the UI layer to properly validate data structures before they are passed deeper into the application logic for execution. In modern web browsers, the user interface often serves as a gateway for interpreting complex HTML constructs, CSS properties, and JavaScript objects. When these inputs contain malformed or specially crafted sequences that exploit edge cases in parsing routines, the browser may misinterpret the intent of the data, leading to memory corruption or logical errors that bypass standard security checks.
The operational impact of this vulnerability is severe due to its potential for remote code execution outside the sandbox environment. Web browsers typically operate within a restricted sandboxed context to limit the damage caused by malicious web content. However, when input validation fails in components like the UI renderer, an attacker can craft a specific HTML page that triggers undefined behavior during processing. This crafted payload exploits the discrepancy between expected and actual data formats, allowing it to escape the isolated execution environment of the browser tab or frame. Once outside this sandbox, the malicious code gains elevated privileges on the underlying Android operating system, potentially enabling full device compromise, unauthorized access to sensitive user data, installation of persistent malware, or use of the device as part of a botnet.
From an industry standards perspective, this vulnerability aligns with CWE-20 Improper Input Validation and often involves elements of CWE-787 Out-of-bounds Write if memory corruption is involved in the exploitation chain. The attack vector corresponds to ATT&CK technique T1189 Drive-by Compromise, where users are lured into visiting a malicious website that exploits software vulnerabilities without any direct interaction beyond loading the page. Additionally, the escape from sandbox restrictions relates to ATT&CK tactic TA0005 Defense Evasion and specifically techniques associated with container or VM escape depending on the specific implementation details of Chrome's multi-process architecture on Android.
Mitigation strategies for this vulnerability primarily involve immediate software updates. Users running Google Chrome on Android must upgrade to version 156.0.8078.73 or later, where these input validation checks have been hardened and edge cases in the UI processing logic have been addressed by Chromium developers. For organizations deploying managed browsers, ensuring that automatic update policies are enforced is critical to prevent exposure during the window of vulnerability. Furthermore, while technical patches are the primary defense, users should exercise caution when visiting untrusted websites or clicking on links from unknown sources, as social engineering remains a common delivery mechanism for such drive-by exploits. Security teams should also monitor for indicators of compromise related to unusual network traffic originating from browser processes and ensure that endpoint detection and response solutions are configured to flag suspicious execution patterns in system memory.