CVE-2023-45233 is a vulnerability identified in the TianoCore edk2 project, which is an open-source implementation of the UEFI firmware. The issue lies within the Network Package component, where the code responsible for parsing IPv6 Destination Options headers improperly handles the PadN option. Specifically, the parsing logic contains a loop with an unreachable exit condition (classified under CWE-835), resulting in an infinite loop when processing crafted IPv6 packets containing a malicious PadN option. This infinite loop can cause the firmware to hang or become unresponsive, effectively leading to a denial-of-service (DoS) condition at the firmware level. The vulnerability has a CVSS v3.1 score of 7.5, indicating high severity, with an attack vector of network (AV:N), no required privileges (PR:N), no user interaction (UI:N), and impacts availability (A:H) only, without affecting confidentiality or integrity. The flaw affects the edk2-stable202308 version, and no patches have been published yet. Although no active exploits are known, the vulnerability could be leveraged by an attacker to disrupt system availability remotely by sending specially crafted IPv6 packets to vulnerable devices during early boot or runtime firmware network operations. This could impact devices relying on edk2 firmware implementations, including servers, workstations, and embedded systems that utilize UEFI network boot or network services at the firmware level.

For European organizations, the primary impact of CVE-2023-45233 is a potential denial-of-service condition at the firmware level, which could cause systems to hang or become unresponsive during boot or network operations. This can lead to operational disruptions, downtime, and potential loss of availability for critical services. Organizations in sectors such as telecommunications, energy, finance, and government, which rely heavily on robust and secure firmware for their infrastructure, may face increased risk. The inability to boot or maintain firmware network functionality could delay incident response or recovery efforts. Additionally, the vulnerability could be exploited as part of a larger attack chain to disrupt business continuity. Since the vulnerability does not affect confidentiality or integrity, data breaches are less likely, but the availability impact alone can have significant operational and financial consequences. The lack of known exploits provides a window for proactive mitigation, but the network-based attack vector means that exposure is possible remotely, increasing the threat surface.

Given the absence of an official patch, European organizations should implement immediate network-level mitigations to reduce exposure. This includes deploying IPv6 packet filtering rules on firewalls and intrusion prevention systems to detect and block malformed or suspicious IPv6 Destination Options headers, particularly those containing PadN options that could trigger the infinite loop. Network segmentation and limiting exposure of firmware network services to untrusted networks can reduce attack vectors. Organizations should monitor network traffic for anomalous IPv6 packets and implement logging to detect potential exploitation attempts. Firmware vendors and system integrators should be engaged to prioritize patch development and deployment for affected edk2 versions. Where possible, disable unnecessary network boot or firmware network services until patches are available. Regular firmware integrity checks and system monitoring can help identify systems affected by the vulnerability. Finally, organizations should maintain updated asset inventories to identify devices running vulnerable edk2 firmware versions to prioritize remediation efforts.