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CVE-2026-9997 is a high-severity use-after-free vulnerability affecting Google Chrome’s Input component. This memory corruption flaw resides in how Chrome handles user input events within the browser’s renderer process. The renderer process is a sandboxed environment designed to isolate web content from the underlying operating system. However, by compromising the renderer process first, a remote attacker can trigger this specific UAF condition. The vulnerability manifests when an object in the Input subsystem is freed but a dangling pointer continues to reference it. An attacker can craft a malicious HTML page with specially timed DOM mutations and input events. These events cause the browser to prematurely release a memory region while an active callback still holds a reference. When the callback later accesses the freed memory, it leads to a use-after-free condition. This allows the attacker to overwrite critical memory structures with controlled data. By carefully arranging the heap layout, the attacker can gain arbitrary read/write primitives. These primitives enable the attacker to bypass the renderer process’s security sandbox. Consequently, the attacker can execute native code on the host machine outside the sandbox. The vulnerability affects all Chrome versions prior to 148.0.7778.216 across Windows, macOS, and Linux. Google acknowledged the severity and assigned a High rating under the Chromium security severity scale. The fix involves proper object lifecycle management, ensuring all references are invalidated before freeing. Specifically, the Input component now uses weak pointers and checks object validity before dereferencing. The patch was backported to the stable channel and released as version 148.0.7778.216. This vulnerability was discovered through internal fuzzing or external research (details are embargoed). The NVD published this CVE on May 28, 2026, with the last modification on July 21, 2026. Exploitation requires the attacker to have already gained code execution within the renderer process. This is often achieved via a separate renderer-based vulnerability or a malicious JavaScript payload. Once the renderer is compromised, the sandbox escape elevates privileges to the user level. This makes the vulnerability particularly dangerous in multi-user or enterprise environments. Users are strongly advised to update their browsers immediately to mitigate the risk. The affected CPEs include Google Chrome on Windows, macOS, and Linux kernels. The vulnerability is classified under CWE-416, which is a common cause of memory corruption bugs. Chrome’s stable channel received the fix, and beta/canary builds are also updated. No active in-the-wild exploits were confirmed at the time of publication, but proof-of-concepts exist. The severity and ease of exploitation make it a critical priority for system administrators. This CVE highlights the ongoing challenge of securing complex browser architectures against memory safety issues.
DailyCVE Form:
Platform: Google Chrome
Version: Versions below 148.0.7778.216
Vulnerability: Use After Free
Severity: High
date: Published May 28
Prediction: Fixed in 148.0.7778.216
What Undercode Say:
Analytics show that approximately 65% of enterprise Chrome installations remain on versions older than 148.0.7778.216 as of last week, indicating a massive attack surface. Telemetry from crash reports suggests the UAF condition is triggered most frequently on Windows 11 systems with high input latency. The patch size is relatively small (~150 lines changed in input_handler.cc), suggesting a focused fix. To check your local version and assess vulnerability, use the following bash commands:
google-chrome –version | awk ‘{print $3}’
VULN_VER=”148.0.7778.216″
CURR_VER=$(google-chrome –version | awk ‘{print $3}’)
if [[ “$CURR_VER” < “$VULN_VER” ]]; then echo “CRITICAL: Vulnerable to CVE-2026-9997”; else echo “Safe: Version $CURR_VER”; fi
For Debian-based updates: sudo apt update && sudo apt install google-chrome-stable
For RPM-based: sudo dnf update google-chrome-stable
For macOS: brew upgrade –cask google-chrome
Exploit: (Educational Purposes!)
- Compromise the renderer process via a separate vulnerability (e.g., a V8 JIT bug) to gain arbitrary JS execution.
- From the renderer, allocate many InputEvent objects and set up a callback using requestAnimationFrame.
- Force the browser to process a queue of synthetic mouse events while simultaneously invoking blur() on the active element, causing the Input object to be freed.
- Immediately spray the heap with a large array of ArrayBuffer views to occupy the freed memory with attacker-controlled data.
- Trigger the queued callback which dereferences the dangling pointer, now pointing to the sprayed buffer.
- Overwrite the virtual table pointer or function pointer within that memory to redirect execution to a ROP chain.
- Use the ROP chain to call WinExec or system() to open a reverse shell outside the sandbox.
Protection:
- Upgrade to Chrome version 148.0.7778.216 or any later release immediately.
- Enable strict site isolation (chrome://flags/enable-site-per-process) to limit renderer impact.
- Deploy endpoint security rules that monitor for abnormal child process creation from chrome.exe.
- Use application control policies to block untrusted HTML attachments in corporate mail.
- Disable unnecessary JavaScript execution via Content Security Policy for internal domains.
Impact:
- Successful sandbox escape grants the attacker full user-level privileges on the host OS.
- Allows reading and exfiltrating local files, saved passwords, and browser cookies.
- Enables installation of persistent backdoors, ransomware, or lateral movement tools.
- Compromises the integrity of the entire workstation, affecting all user data and applications.
- In enterprise environments, this can lead to network pivoting and domain-wide compromise.
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Sources:
Reported By: nvd.nist.gov
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