CVE-2025-1290: Chrome OS Use-After-Free Vulnerability

CVE-2025-1290 Overview

A race condition Use-After-Free vulnerability exists in the virtio_transport_space_update function within the Linux Kernel 5.4 on ChromeOS. This vulnerability arises from concurrent allocation and freeing of the virtio_vsock_sock structure during an AF_VSOCK connect syscall, which can occur before a worker thread accesses it. This results in a dangling pointer that can potentially lead to kernel code execution.

Critical Impact

This Use-After-Free vulnerability in the kernel's virtio transport layer could allow attackers to execute arbitrary code with kernel privileges, potentially leading to complete system compromise on affected ChromeOS devices.

Affected Products

• Google Chrome OS version 15474.84.0
• Linux Kernel version 5.4
• ChromeOS-based devices running vulnerable kernel versions

Discovery Timeline

• 2025-04-17 - CVE-2025-1290 published to NVD
• 2025-07-11 - Last updated in NVD database

Technical Details for CVE-2025-1290

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption flaw that occurs when a program continues to use memory after it has been freed. In this specific case, the race condition exists within the virtio_transport_space_update function, which is part of the virtio-vsock transport implementation in the Linux kernel.

The AF_VSOCK address family provides communication between virtual machines and their hosts. During the connection establishment process, the virtio_vsock_sock structure is allocated to maintain socket state. The vulnerability manifests when a worker thread attempts to access this structure while another thread is simultaneously freeing it, creating a classic Time-of-Check to Time-of-Use (TOCTOU) scenario.

The network-accessible attack vector combined with the requirement for high attack complexity indicates that while the vulnerability is remotely exploitable, successful exploitation requires precise timing to win the race condition. Successful exploitation could result in arbitrary kernel code execution, leading to complete system compromise.

Root Cause

The root cause lies in improper synchronization mechanisms protecting the virtio_vsock_sock structure during AF_VSOCK connect operations. The kernel fails to properly lock or reference count the socket structure before worker threads access it, allowing concurrent free operations to invalidate the pointer. This lack of proper memory lifecycle management creates a window where the structure can be deallocated while still being referenced by active kernel threads.

Attack Vector

The vulnerability is exploitable via network-based attacks targeting the virtio transport layer. An attacker would need to:

1. Initiate multiple concurrent AF_VSOCK connect syscalls to trigger allocation of virtio_vsock_sock structures
2. Time the operations to create a race condition between allocation, use, and deallocation
3. Win the race condition to cause the worker thread to access freed memory
4. Potentially spray the heap to control the contents of the freed memory region
5. Achieve arbitrary code execution in kernel context

The high attack complexity reflects the need for precise timing and potentially multiple attempts to successfully exploit this race condition. However, the lack of required privileges or user interaction makes this vulnerability particularly concerning for exposed systems.

Detection Methods for CVE-2025-1290

Indicators of Compromise

• Unexpected kernel crashes or panics related to virtio-vsock operations
• Abnormal memory access patterns in kernel logs referencing virtio_transport_space_update
• Suspicious AF_VSOCK connection attempts with unusual timing patterns
• Evidence of heap spray techniques targeting kernel memory

Detection Strategies

• Monitor for kernel oops or panic messages containing references to virtio_transport or vsock functions
• Implement kernel-level memory access monitoring to detect use-after-free access patterns
• Deploy endpoint detection and response (EDR) solutions capable of monitoring kernel-level anomalies
• Configure audit logging for socket creation syscalls involving AF_VSOCK address family

Monitoring Recommendations

• Enable kernel crash dump collection to capture forensic evidence of exploitation attempts
• Implement system integrity monitoring on ChromeOS devices to detect unauthorized kernel modifications
• Configure network monitoring to identify unusual communication patterns targeting virtual socket interfaces
• Review system logs for repeated connection failures or timeouts involving virtio-vsock

How to Mitigate CVE-2025-1290

Immediate Actions Required

• Update ChromeOS to the latest stable channel release that includes the security patch
• Restrict network access to affected systems until patches can be applied
• Implement network segmentation to limit exposure of vulnerable ChromeOS devices
• Monitor systems for signs of exploitation attempts while awaiting patches

Patch Information

Google has addressed this vulnerability in ChromeOS. Administrators should ensure all managed ChromeOS devices are updated to receive the security fix. Detailed information about the patch is available through the Chromium Issue Tracker and Google Issue Tracker.

For enterprise environments managing ChromeOS fleets, ensure that automatic updates are enabled and verify patch deployment across all devices. The fix addresses the race condition by implementing proper synchronization mechanisms to protect the virtio_vsock_sock structure lifecycle.

Workarounds

• Disable or restrict AF_VSOCK functionality if not required for business operations
• Implement network access controls to limit exposure of affected systems
• Deploy additional security monitoring on systems where immediate patching is not feasible
• Consider isolating affected ChromeOS devices in restricted network segments until updates are applied

# Verify ChromeOS version includes security fixes
# Navigate to Settings > About ChromeOS to check current version
# Ensure version is newer than 15474.84.0 with applicable security patches

# For enterprise environments, verify update policies
# Check that auto-update is enabled in Google Admin Console
# Devices > Chrome > Settings > Device update settings