CVE-2021-0155 is a medium-severity vulnerability affecting certain Intel processors, specifically related to unchecked return values in the BIOS firmware. This flaw allows a privileged local user to potentially cause information disclosure by exploiting improper handling of BIOS firmware responses. The vulnerability arises because the BIOS firmware does not properly verify or handle return values, which can lead to leakage of sensitive information. Exploitation requires local access with some level of privilege, but no user interaction is needed once the attacker has such access. The vulnerability impacts confidentiality but does not affect integrity or availability. The CVSS 3.1 base score is 5.5, reflecting a medium severity with attack vector limited to local access, low attack complexity, and low privileges required. No known exploits are reported in the wild, and no patches are explicitly linked in the provided data, though Intel likely has released firmware updates addressing this issue. The CWE-252 classification indicates a failure to check return values, a common software weakness that can lead to unexpected behavior or security issues. This vulnerability is significant because BIOS firmware operates at a very low level, and flaws here can undermine system security foundations.

For European organizations, the primary impact of CVE-2021-0155 is the potential exposure of sensitive information through local privilege abuse. Since exploitation requires local privileged access, the threat is mainly relevant in environments where multiple users have elevated privileges or where attackers can gain such access through other means (e.g., lateral movement after initial compromise). Information disclosure at the BIOS level could expose cryptographic keys, system configuration details, or other sensitive data that could facilitate further attacks or data breaches. This risk is particularly critical for sectors with high security requirements such as finance, government, healthcare, and critical infrastructure. The vulnerability does not directly allow remote exploitation or denial of service, limiting its impact to confidentiality breaches in controlled environments. However, the presence of this flaw in widely deployed Intel processors means that many European enterprises and public sector organizations could be affected if firmware updates are not applied promptly.

Mitigation should focus on applying the latest BIOS/firmware updates provided by Intel or system manufacturers as soon as they become available, as these updates typically address unchecked return value handling. Organizations should implement strict access controls to limit privileged local access only to trusted administrators and use endpoint protection solutions to detect and prevent unauthorized privilege escalation attempts. Regular auditing of privileged accounts and monitoring for unusual local activity can help detect attempts to exploit this vulnerability. Additionally, employing hardware-based security features such as Intel Trusted Execution Technology (TXT) or Intel Boot Guard can help protect BIOS integrity and reduce the risk of exploitation. Organizations should also ensure secure configuration management and maintain an inventory of affected hardware to prioritize patching efforts. Since no user interaction is required, user training is less relevant, but awareness among system administrators about the importance of firmware updates is critical.