Google Chrome CVE-2026-106409

Exploitation requires the attacker to have ALREADY compromised the Chrome renderer process on a macOS host - this is explicitly stated and is the primary limiting factor, making the bug a sandbox-escape stage in a larger exploit chain rather than a standalone remote compromise. The vulnerable code path is the WebAppInstalls component, and the trigger is crafted network traffic processed after renderer compromise. It affects only Chrome on macOS prior to 155.0.8059.39 (other platforms not indicated as affected), and CVSS AC:H reflects the non-trivial conditions needed to successfully resolve the incorrect reference and break out. A vendor patch is available, so patched installs are not exploitable.

This is a sandbox escape (CWE-706, Incorrect Reference Resolution) in Chrome's WebAppInstalls component on macOS, and its real-world risk is highly conditional. The CVSS 8.3 vector (AV:N/AC:H/PR:N/UI:R/S:C) scores high primarily because of the scope change (S:C) and full C/I/A impact of breaking out of the renderer sandbox, but the description makes clear this is NOT a standalone remote exploit: the attacker must have ALREADY compromised the renderer process. This is a conflict worth flagging - the vector marks PR:N (no privileges), yet the description's precondition ('a remote attacker who had compromised the renderer process') means a prior exploit/foothold is effectively required, so in isolation this is a second-stage bug rather than a single-shot RCE. The AC:H rating is consistent with the difficulty of chaining it. Chromium itself rated the security severity only Medium, which aligns with the chain-dependent nature despite the 8.3 NVD-style score. No EPSS score, KEV listing, or POC was provided in the input, so there is no evidence of active exploitation or public exploit code. Bottom line: treat as a standard high-priority browser patch (patch is available) rather than an emergency; the headline 8.3 overstates standalone risk because real exploitation requires a pre-existing renderer compromise.

An attacker first compromises the Chrome renderer process on a macOS target (for example via a separate renderer-RCE bug in a malicious or attacker-controlled web page), then abuses the incorrect reference resolution in WebAppInstalls by sending crafted network traffic to escape the sandbox and run arbitrary code with broader privileges on the host. No public exploit code was identified at time of analysis, and the attack is high-complexity (CVSS AC:H) and dependent on already controlling the renderer.