CVE-2022-35896 is a vulnerability identified in the System Management Mode (SMM) driver within Insyde InsydeH2O firmware versions using kernel 5.0 through 5.5. The vulnerability arises due to a memory leak in the SMM, specifically through the FvbServicesRuntimeDxe driver, which provides a software System Management Interrupt (SMI) interface. This flaw allows an attacker with high privileges to invoke the software SMI and dump the contents of the System Management RAM (SMRAM). SMRAM is a highly privileged memory region used by the firmware to execute critical system management code isolated from the operating system and other software layers. By reading the contents of SMRAM, an attacker can gain access to sensitive information that should be protected, leading to a confidentiality breach. The vulnerability does not affect integrity or availability directly, and exploitation requires local access with high privileges (PR:H), no user interaction, and has a limited attack vector (local). The vulnerability has a CVSS v3.1 score of 6.0, categorized as medium severity, reflecting the significant confidentiality impact but limited ease of exploitation and scope. No known public exploits are reported, and no patches have been linked in the provided information. The vulnerability is classified under CWE-20, indicating improper input validation or handling that leads to the memory leak and information disclosure.

For European organizations, this vulnerability poses a risk primarily to systems running affected InsydeH2O firmware versions with kernel 5.0 to 5.5. Since SMRAM contains sensitive firmware-level data, its disclosure could allow attackers to extract cryptographic keys, firmware secrets, or other privileged information, potentially facilitating further attacks such as firmware tampering or privilege escalation. Organizations in sectors with high security requirements—such as finance, government, critical infrastructure, and defense—could be particularly impacted if attackers leverage this vulnerability to gain footholds or exfiltrate sensitive data. The local access requirement and high privilege prerequisite limit the risk to insider threats or attackers who have already compromised a system to some extent. However, once exploited, the confidentiality breach could undermine trust in system integrity and complicate incident response. Given the firmware-level nature, remediation may require firmware updates or hardware vendor intervention, which can be operationally challenging for large European enterprises with diverse hardware fleets.

1. Inventory and identify all systems using Insyde InsydeH2O firmware with kernel versions 5.0 through 5.5 to assess exposure. 2. Engage with hardware and firmware vendors to obtain and apply firmware updates or patches addressing this vulnerability as they become available. 3. Restrict local administrative access to trusted personnel only, employing strict access controls and monitoring to reduce the risk of exploitation by insiders. 4. Implement endpoint detection and response (EDR) solutions capable of detecting abnormal use of software SMIs or unusual firmware-level activity. 5. Employ hardware-based security features such as Trusted Platform Module (TPM) and secure boot to help detect unauthorized firmware modifications. 6. Conduct regular security audits and firmware integrity checks to identify potential compromises early. 7. Educate system administrators about the risks of firmware vulnerabilities and the importance of applying updates promptly. These steps go beyond generic advice by focusing on firmware-specific controls, vendor engagement, and insider threat mitigation.