CVE-2026-9915: Chrome ANGLE Heap Buffer Overflow Sandbox Escape

Technical summary

CVE-2026-9915 is a heap buffer overflow (CWE-122) in ANGLE, Chrome's GPU abstraction layer. The vulnerability exists in versions before 148.0.7778.216 and requires an attacker with an existing renderer process compromise to trigger via crafted HTML content. The CVSS 3.1 score of 8.3 reflects high confidentiality, integrity, and availability impact with high attack complexity (requiring prior compromise and user interaction). The vulnerability enables sandbox escape, allowing code execution at the OS privilege level rather than being confined to the browser sandbox.

Business impact

Successful exploitation could allow an attacker to move from a compromised renderer process to full system compromise. In practical terms, if an attacker has already achieved code execution within Chrome (through a separate vulnerability or social engineering), this flaw provides a path to escape the sandbox and access the underlying operating system. This elevates the threat from browser-level compromise to machine-level compromise, potentially enabling theft of system credentials, installation of persistent malware, or lateral movement across a network.

Affected systems

Google Chrome versions prior to 148.0.7778.216 are affected. Users on older versions across Windows, macOS, and Linux should prioritize updating. The vulnerability requires the renderer process to be compromised first, so it is primarily a concern in attack chains rather than as a direct attack surface.

Exploitability

This is not a directly exploitable vulnerability in isolation. It requires an attacker to have already compromised Chrome's renderer process, either through a separate vulnerability in the browser, a malicious website, or social engineering. Once renderer access is achieved, the attacker can trigger the heap overflow via crafted HTML to escape the sandbox. The attack complexity is high due to the prerequisite compromise requirement, and it requires user interaction (rendering the malicious HTML page). No known public exploits are tracked in CISA's KEV catalog.

Remediation

Update Google Chrome to version 148.0.7778.216 or later. The patch addresses the heap buffer overflow in ANGLE. Organizations should verify the specific version number through Google's official release notes and ensure automatic updates are enabled or deploy updates through endpoint management tools. Prioritize this update for systems handling sensitive data or high-risk users (developers, researchers, high-profile individuals).

Patch guidance

Google Chrome auto-updates by default; however, users should verify they are on version 148.0.7778.216 or later by navigating to Chrome Settings > About Chrome, which will display the current version and initiate an update if available. In enterprise environments, deploy via your software distribution platform (WSUS, MDM, or equivalent) to ensure consistent patching. If auto-update is disabled, manually trigger updates across your fleet. This patch should be prioritized but does not require emergency (same-day) response unless you have specific indicators of renderer compromise in your environment.

Detection guidance

Detecting active exploitation is challenging because it requires both prior renderer compromise and subsequent sandbox escape activity. Monitor for: (1) unusual Chrome process behavior, such as unexpected child processes spawned from the renderer or access to system resources outside normal browser functions; (2) heap corruption artifacts in crash logs (look for out-of-bounds memory access patterns in ANGLE-related crashes); (3) suspicious HTML content loaded in browsers (if possible, analyze browsing history for malicious sites in incident investigations). Endpoint Detection and Response (EDR) tools should flag any Chrome renderer attempting to execute OS-level system calls or spawn processes.

Why prioritize this

Although the CVSS score is 8.3 (HIGH) and the Chromium severity is rated High, this vulnerability is a secondary stage in an attack chain—not a direct entry point. Prioritize patching based on: (1) whether your environment has active indicators of renderer compromise; (2) the sensitivity of the systems and users involved; (3) your organization's general Chrome update cadence. Most organizations should patch within their normal monthly cycle. Extremely high-risk users (security researchers, journalists, executives in targeted sectors) should receive patches immediately. The lack of KEV listing indicates this is not yet actively exploited in the wild at scale.

Risk score, explained

The CVSS 3.1 score of 8.3 reflects the potential for high impact (C:H/I:H/A:H) combined with high attack complexity (AC:H) and the requirement for network attack vector with user interaction. The network vector assumes the attacker can deliver malicious HTML; the high complexity accounts for the prerequisite renderer compromise. The score appropriately weights this as a serious but not critical threat in isolation—the true risk depends on the prevalence of prior renderer compromises in your threat model.

Frequently asked questions