CVE-2026-33197 in AptioV
Summary
by MITRE • 09/08/2026
AMI APTIOV contains a vulnerability in BIOS where a privileged user may cause the “Incomplete List of Disallowed Inputs” by local access. Successful exploitation of this vulnerability may lead to arbitrary code execution and impact system Confidentiality, Integrity, and Availability.
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Analysis
by VulDB Data Team • 09/08/2026
The AMI Aptio V firmware platform contains a critical security flaw rooted in insufficient validation of input data during BIOS initialization routines. This vulnerability is classified under the Common Weakness Enumeration as CWE-20, which denotes an Incomplete List of Disallowed Inputs or Improper Restriction of Excessive Authentication Attempts. The core technical issue arises from the system's failure to rigorously sanitize and validate specific configuration parameters or command inputs provided by a user with local administrative privileges before these inputs are processed by lower-level firmware components. Because the BIOS operates at Ring 0, it possesses unrestricted access to hardware resources and memory spaces that are typically isolated in standard operating systems. When privileged input is not adequately filtered against a comprehensive whitelist of allowed values or blacklist of known malicious patterns, the system may accept malformed or unexpected data structures that trigger unintended execution paths within the firmware codebase.
The operational impact of this vulnerability is severe due to the elevated privilege level required for exploitation and the foundational nature of BIOS in the boot process. A local attacker with administrative rights can leverage this flaw to bypass standard security controls embedded in the UEFI environment. By crafting specific inputs that exploit the incomplete validation logic, an adversary can achieve arbitrary code execution within the pre-boot environment. This capability allows the injection of malicious payloads such as rootkits or bootkits that persist across reboots and are difficult for traditional endpoint detection solutions to identify because they operate below the operating system layer. The compromise affects all three pillars of the CIA triad: confidentiality is breached through potential exfiltration of sensitive data stored in NVRAM or memory; integrity is compromised as attackers can modify boot sequences, firmware settings, or kernel modules without authorization; and availability is threatened by causing system crashes or preventing successful OS initialization through corrupted state manipulation.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK techniques related to persistence and privilege escalation within the Pre-OS Boot stage. Attackers utilizing such flaws often aim to establish persistent access that survives operating system reinstalls or firmware updates if not specifically targeted for remediation. The lack of comprehensive input validation represents a fundamental design flaw in how the BIOS handles configuration changes, reflecting a broader industry challenge where performance optimization sometimes takes precedence over rigorous security checking during development cycles. This specific instance highlights the risk associated with trusted administrator accounts being compromised or misused to escalate privileges further into firmware-level control.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is the application of vendor-provided BIOS updates that patch the input validation logic, ensuring all user-supplied data undergoes strict type checking and range verification before execution. Organizations should enforce strict physical security controls to prevent unauthorized local access to management consoles where such privileged actions can be initiated. Additionally implementing UEFI Secure Boot with a properly configured key database ensures that only signed bootloaders are executed, which can mitigate the impact of some firmware-based attacks by preventing unsigned code from running during startup. Regular auditing of BIOS settings and monitoring for anomalies in system behavior post-update is also recommended to detect potential exploitation attempts or residual malware presence.