CVE-2026-12018: 
vulnerability analysis and mitigation

CVE-2026-12018 is a privilege escalation vulnerability caused by an inappropriate implementation in the Mojo IPC framework within Google Chrome on Windows. It allows a local attacker to perform OS-level privilege escalation via a malicious file. The vulnerability affects all Google Chrome versions prior to 149.0.7827.114/115 on Windows. It was reported internally by Google on 2026-05-26 and publicly disclosed on June 11, 2026, as part of a 27-fix stable channel update. It carries a CVSS v3.1 base score of 8.8 (High) (Chrome Releases, GitHub Advisory).

The root cause is classified as CWE-269 (Improper Privilege Management), stemming from an inappropriate implementation in Chrome's Mojo inter-process communication (IPC) subsystem on Windows. Mojo is the cross-platform IPC framework used by Chromium to facilitate communication between browser processes; a flaw in its implementation can allow a local attacker to abuse privilege boundaries. Exploitation requires the attacker to place or interact with a malicious file on the target system, after which the Mojo implementation flaw can be leveraged to escalate OS-level privileges. The Chromium issue tracker entry is referenced as issue 516808201, though full technical details remain restricted pending broad user patching (Chrome Releases, GitHub Advisory).

Successful exploitation allows a local attacker to escalate their privileges to a higher OS-level privilege on Windows systems running a vulnerable version of Chrome. This can result in high confidentiality, integrity, and availability impact — an attacker who gains elevated privileges could access sensitive data, modify system files, install persistent malware, or disable security controls. The scope is limited to the local Windows system, but elevated privileges could facilitate lateral movement within a network or enable further compromise of the affected host (GitHub Advisory, Chrome Releases).

Google has released a fix in Chrome stable channel version 149.0.7827.114 for Linux and 149.0.7827.114/.115 for Windows and Mac. Users and administrators should update Google Chrome to version 149.0.7827.115 or later immediately. As additional hardening measures, restrict file write permissions on Windows systems to trusted users only, and implement file integrity monitoring to detect unauthorized file modifications. Enterprise administrators can enforce Chrome updates via policy management tools (Chrome Releases, GitHub Advisory).

The vulnerability was part of a large Chrome stable update addressing 27 security issues, including five rated Critical, which drew broad attention from the security community. Downstream Linux distributions including Debian, Fedora (versions 43 and 44), and openSUSE issued Chromium security updates in response. Microsoft also published a reference entry for the CVE. Social media activity was limited, with brief mentions on Mastodon and security aggregator sites (Chrome Releases).