CVE-2025-12464 in QEMU
Summary
by MITRE • 11/01/2025
A stack-based buffer overflow was found in the QEMU e1000 network device. The code for padding short frames was dropped from individual network devices and moved to the net core code. The issue stems from the device's receive code still being able to process a short frame in loopback mode. This could lead to a buffer overrun in the e1000_receive_iov() function via the loopback code path. A malicious guest user could use this vulnerability to crash the QEMU process on the host, resulting in a denial of service.
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Analysis
by VulDB Data Team • 12/23/2025
The vulnerability CVE-2025-12464 represents a critical stack-based buffer overflow in QEMU's e1000 network device implementation that stems from a code refactoring issue in the network subsystem. This flaw manifests when the network device processes short frames in loopback mode, creating a scenario where memory corruption can occur during frame padding operations. The vulnerability emerged from the removal of frame padding logic from individual network device implementations and its centralization in the net core code, which inadvertently created a gap in the loopback processing path. The e1000_receive_iov() function becomes susceptible to buffer overruns when handling specific frame sizes during loopback operations, as the refactored code fails to properly validate frame lengths before processing. This represents a classic CWE-121 stack-based buffer overflow vulnerability that can be exploited through improper memory management during network frame processing.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling more sophisticated attacks within virtualized environments. When exploited, the buffer overflow can cause the QEMU process to crash, leading to complete system disruption for all virtual machines running on that host. This vulnerability particularly affects systems using QEMU with e1000 network devices in loopback mode, which is commonly used in testing environments and certain network configurations. The attack vector requires a malicious guest user with access to the virtual machine, making it a privilege escalation concern in multi-tenant virtualization environments. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Endpoint Denial of Service) and potentially T1059.001 (Command and Scripting Interpreter) if the attacker can leverage additional privileges after initial exploitation. The vulnerability's impact is amplified in cloud and data center environments where multiple virtual machines share the same host infrastructure, potentially enabling a single compromised guest to affect the entire host system.
Mitigation strategies for CVE-2025-12464 should prioritize immediate patching of QEMU installations to address the buffer overflow in the e1000 network device implementation. System administrators should disable loopback mode for e1000 devices when not required, as this eliminates the vulnerable code path entirely. Network segmentation and access controls should be implemented to limit guest user privileges and reduce the attack surface for potential exploitation. Monitoring systems should be configured to detect unusual QEMU process crashes or network behavior that might indicate exploitation attempts. Organizations should also consider implementing virtualization-specific security controls such as hypervisor hardening, network traffic inspection, and regular vulnerability assessments of virtualized environments. The fix should include proper bounds checking in the e1000_receive_iov() function to validate frame sizes before processing, ensuring that the centralized frame padding logic properly handles all frame length scenarios. Additionally, implementing proper input validation and memory safety mechanisms in the network core code will prevent similar issues from occurring in other network device implementations. Regular security updates and penetration testing of virtualization environments are essential to maintain protection against such vulnerabilities that can compromise the integrity of entire host systems through guest exploitation.