CVE-2024-21961 in EPYC 7002 Processors
Summary
by MITRE • 02/13/2026
Improper restriction of operations within the bounds of a memory buffer in PCIe® Link could allow an attacker with access to a guest virtual machine to potentially perform a denial of service attack against the host resulting in loss of availability.
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Analysis
by VulDB Data Team • 02/26/2026
This vulnerability resides within the PCIe link implementation where improper memory buffer boundary restrictions create a potential attack surface for malicious actors. The flaw manifests when a guest virtual machine gains access to the PCIe interface, allowing adversaries to manipulate memory operations beyond their intended boundaries. Such buffer overflows or underflows can occur during data transfer processes between virtualized components and physical hardware, potentially leading to system instability and complete service disruption.
The technical implementation of this vulnerability stems from inadequate validation of memory access operations within PCIe link protocols. When virtual machines interact with physical hardware through PCIe interfaces, the system should enforce strict boundary checks to prevent unauthorized memory manipulation. However, the flaw allows attackers to exceed these boundaries through carefully crafted memory operations that exploit gaps in the validation mechanisms. This type of vulnerability aligns with CWE-129, which addresses improper validation of array indices and buffer bounds, and specifically relates to the broader category of buffer overflow conditions that can be leveraged for denial of service attacks.
The operational impact of CVE-2024-21961 extends beyond simple service disruption to potentially compromise entire virtualized environments. An attacker with guest access can trigger memory corruption that affects the host system's PCIe subsystem, leading to system crashes, data loss, and complete service unavailability. This vulnerability is particularly dangerous in cloud computing environments where multiple tenants share the same physical infrastructure, as a successful attack could affect not just the targeted guest but also other virtual machines hosted on the same physical hardware. The attack vector requires only guest-level access, making it accessible to malicious actors who may have legitimate but unauthorized access to virtualized resources.
Mitigation strategies should focus on implementing robust memory boundary checking mechanisms within PCIe link implementations and strengthening virtualization layer security. Organizations should deploy updated firmware and hypervisor patches that address the buffer validation gaps in PCIe operations. Network segmentation and access controls can limit the potential impact of such vulnerabilities by reducing guest access privileges and implementing strict isolation between virtual machines. Additionally, continuous monitoring of PCIe link operations and memory access patterns can help detect anomalous behavior indicative of exploitation attempts. This vulnerability demonstrates the critical importance of maintaining secure virtualization environments and aligns with ATT&CK technique T1489, which covers denial of service attacks through system resource manipulation. The implementation of hardware-based memory protection features and regular security assessments of virtualized infrastructure can significantly reduce the risk of exploitation.