CVE-2026-7917 Overview
CVE-2026-7917 is a use-after-free vulnerability [CWE-416] in the Fullscreen component of Google Chrome on Windows. The flaw affects Chrome versions prior to 148.0.7778.96. A remote attacker who has already compromised the renderer process can exploit this issue to perform a sandbox escape through a crafted HTML page. Google rates the underlying Chromium security severity as High. The vulnerability requires user interaction and a successful prior renderer compromise, which raises attack complexity. Successful exploitation breaks the Chrome sandbox boundary and allows code execution in a higher-privileged process context.
Critical Impact
Sandbox escape from a compromised renderer enables attackers to break out of Chrome's process isolation and execute code outside the renderer sandbox on Windows hosts.
Affected Products
- Google Chrome on Windows prior to 148.0.7778.96
- Microsoft Windows (host operating system)
- Chromium-based browsers sharing the affected Fullscreen code path
Discovery Timeline
- 2026-05-06 - CVE-2026-7917 published to NVD
- 2026-05-06 - Last updated in NVD database
Technical Details for CVE-2026-7917
Vulnerability Analysis
The vulnerability is a use-after-free condition [CWE-416] in Chrome's Fullscreen implementation. Use-after-free occurs when a program continues to reference memory after it has been freed, allowing attacker-controlled data to occupy the freed allocation. In a browser context, this typically enables manipulation of object virtual tables or function pointers during subsequent operations.
Exploitation in this case is chained. The attacker must first compromise the renderer process, usually through a separate memory corruption or type confusion bug. The Fullscreen use-after-free then serves as the second-stage primitive to escape the renderer sandbox. Sandbox escapes are valuable because they convert limited renderer-level code execution into broader access to the underlying Windows host.
Root Cause
The root cause is improper object lifetime management in the Fullscreen component. Chrome's Fullscreen API coordinates state across the renderer and browser processes. When a referenced object is freed while a pointer to it is still held by another component, subsequent operations dereference the dangling pointer. An attacker who controls the timing and content of allocations from the compromised renderer can place crafted data into the reclaimed memory region.
Attack Vector
The attack chain begins with a victim visiting a crafted HTML page in a vulnerable Chrome version. User interaction is required, consistent with Fullscreen API gestures. After exploiting an initial renderer flaw, the attacker triggers the Fullscreen state transitions that produce the dangling pointer. Controlled reuse of the freed memory then redirects execution flow during the sandbox boundary crossing, yielding a sandbox escape on Windows.
No verified public proof-of-concept code is available for CVE-2026-7917. Refer to the Chromium Issue Tracker Entry for technical detail as it is released, and the Google Chrome Release Update for vendor disclosure information.
Detection Methods for CVE-2026-7917
Indicators of Compromise
- Chrome renderer or browser process crashes referencing the Fullscreen component or content::FullscreenController
- Unexpected child processes spawned by chrome.exe shortly after fullscreen transitions on a web page
- Outbound connections from Chrome host processes to untrusted domains immediately following navigation to attacker-controlled HTML
Detection Strategies
- Inventory installed Chrome versions across Windows endpoints and flag any build below 148.0.7778.96
- Alert on anomalous process lineage where chrome.exe spawns shells, scripting hosts, or LOLBins after browsing activity
- Correlate browser crash telemetry with subsequent privileged process activity to identify potential sandbox escape attempts
Monitoring Recommendations
- Collect Chrome crash dumps and Windows Error Reporting events for triage of Fullscreen-related faults
- Monitor EDR telemetry for code injection, token manipulation, or persistence activity originating from Chrome process trees
- Track navigation events to newly registered or low-reputation domains preceding browser instability
How to Mitigate CVE-2026-7917
Immediate Actions Required
- Update Google Chrome on Windows to version 148.0.7778.96 or later across all managed endpoints
- Force-close and relaunch Chrome to ensure the patched binary is loaded after update deployment
- Audit any Chromium-based browsers and embedded WebView components for equivalent fixes from their vendors
Patch Information
Google has released a fixed build in the Chrome Stable channel for Desktop. Administrators should refer to the Google Chrome Release Update for the official advisory and confirm endpoints report version 148.0.7778.96 or higher. Enterprise deployments using Chrome Browser Cloud Management or Group Policy should verify automatic update channels are not disabled.
Workarounds
- Restrict access to untrusted websites through web proxy or DNS filtering until patching is complete
- Disable the Fullscreen API where feasible using the FullscreenAllowedForUrls and FullscreenAllowed enterprise policies
- Enforce site isolation and reduce browser attack surface by limiting installed extensions on high-risk hosts
# Verify installed Chrome version on Windows endpoints
reg query "HKLM\SOFTWARE\WOW6432Node\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv
# Group Policy: disable Fullscreen as a temporary mitigation
# HKLM\SOFTWARE\Policies\Google\Chrome\FullscreenAllowed = 0 (DWORD)
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
