CVE-2025-32057 identifies a certificate validation vulnerability (CWE-295) in the Bosch Infotainment system ECU used in the Nissan Leaf ZE1 model year 2020. The affected ECU leverages a Redbend service for over-the-air (OTA) provisioning and updates, communicating with backend servers via HTTPS. However, the underlying SSL engine is configured with default settings that do not verify the server's root certificate. This improper validation means the ECU does not confirm the authenticity of the Redbend backend server's TLS certificate chain, allowing an attacker to present a self-signed certificate and impersonate the legitimate update server. Consequently, an attacker positioned on the network path could perform man-in-the-middle (MITM) attacks, delivering malicious payloads or commands to the ECU under the guise of legitimate updates. The vulnerability does not require prior authentication or elevated privileges but does require user interaction, such as triggering an update process. The CVSS v3.1 score is 6.5 (medium severity), reflecting the network attack vector, low attack complexity, no privileges required, and user interaction needed. The impact primarily affects confidentiality, as attackers could intercept or manipulate update data, but integrity and availability are not directly compromised. No public exploits have been reported yet, and Bosch has not published patches at the time of disclosure. The vulnerability was first identified in Nissan Leaf ZE1 vehicles manufactured in 2020, indicating a limited but critical attack surface within automotive infotainment systems.

For European organizations, this vulnerability presents a significant risk to the security of connected vehicles, particularly those operating Nissan Leaf ZE1 models with Bosch Infotainment ECUs. Attackers exploiting this flaw could intercept or manipulate OTA update communications, potentially injecting malicious software or commands that compromise vehicle systems or leak sensitive data. This undermines the confidentiality of vehicle communications and could erode consumer trust in automotive cybersecurity. Fleet operators and automotive service providers relying on secure OTA updates may face operational disruptions or increased costs due to the need for manual updates or incident response. Additionally, regulatory compliance under EU cybersecurity and automotive safety directives may be impacted if vulnerabilities are not promptly addressed. The risk extends to supply chain partners and OEMs who integrate Bosch ECUs, as exploitation could propagate through connected vehicle ecosystems. While no integrity or availability impacts are directly reported, the potential for future exploit variants or chained attacks remains a concern. Overall, the vulnerability highlights the critical need for robust cryptographic validation in automotive OTA update mechanisms to protect European automotive infrastructure and consumers.

1. Bosch should prioritize releasing a firmware update for the affected Infotainment ECU that enforces strict server root certificate validation during TLS handshake, eliminating acceptance of self-signed certificates. 2. Nissan and automotive service providers should implement secure update policies that include cryptographic signature verification of update payloads independent of TLS validation to add defense-in-depth. 3. Network segmentation and monitoring should be employed to detect anomalous traffic patterns indicative of MITM or spoofing attempts targeting OTA update communications. 4. Organizations managing fleets of affected vehicles should establish procedures for manual update verification and incident response in case of suspected compromise. 5. Security teams should audit and harden SSL/TLS configurations in automotive ECUs and backend services to avoid default or insecure settings. 6. User awareness campaigns can help ensure that vehicle operators understand the importance of applying updates only from trusted sources and reporting suspicious behavior. 7. Collaboration with automotive cybersecurity information sharing groups in Europe can facilitate rapid dissemination of patches and threat intelligence related to this vulnerability. 8. OEMs should review and enhance their supply chain security requirements to mandate secure cryptographic practices in all embedded systems.