CVE-2025-3301 identifies a vulnerability in Silicon Labs Series 2 System on Chips (SoCs) and associated modules related to their implementation of cryptographic operations using Curve25519 and Curve448 elliptic curves. Specifically, the vulnerability arises from the lack of Differential Power Analysis (DPA) countermeasures during Elliptic Curve Diffie-Hellman (ECDH) key agreement and Edwards-curve Digital Signature Algorithm (EdDSA) signing operations. DPA is a side-channel attack technique that exploits variations in power consumption during cryptographic computations to extract secret keys. The affected Series 2 SoCs do not have hardware or software protections to mitigate these power side-channel leaks, making them susceptible to attackers capable of measuring power consumption during cryptographic operations. Successful exploitation could lead to the exposure of confidential cryptographic keys, undermining the confidentiality and integrity of communications and data protected by these keys. The vulnerability is categorized under CWE-1255, which relates to comparison logic weaknesses that can be exploited via side-channel attacks. The CVSS v4.0 score is 1.0 (low severity), reflecting the difficulty of exploitation (physical proximity or specialized equipment likely required), and the limited scope of impact. No patches or mitigations have been published by the vendor at this time. The recommended best practice is to use ephemeral keys with the impacted cryptographic curves and operations, thereby limiting the number of exploitable DPA traces an attacker can collect. This approach reduces the risk but does not eliminate the underlying hardware/software vulnerability. No known exploits are currently in the wild, and no user interaction or authentication is required for the vulnerability to be relevant, but physical access or proximity for power measurement is implied. Overall, this vulnerability highlights a hardware-level cryptographic side-channel risk in widely used IoT and embedded devices based on Silicon Labs Series 2 SoCs that implement Curve25519 and Curve448 cryptography without DPA protections.

For European organizations, the impact of this vulnerability depends largely on the deployment of Silicon Labs Series 2 SoCs within their infrastructure, particularly in IoT devices, embedded systems, and secure communication modules. If these devices are used in critical infrastructure, industrial control systems, or secure communications, the exposure of cryptographic keys via DPA attacks could lead to unauthorized data decryption, impersonation, or manipulation of sensitive information. This could compromise confidentiality and integrity of communications and data, potentially leading to operational disruptions or data breaches. However, the low CVSS score and the requirement for physical proximity or access to perform power analysis limit the likelihood of widespread exploitation. Organizations relying on ephemeral keys mitigate risk somewhat, but persistent attackers with physical access could still extract keys. The absence of patches means the vulnerability remains a long-term risk in affected devices. European sectors such as manufacturing, energy, healthcare, and telecommunications that deploy embedded devices with these SoCs may face targeted attacks aiming to extract cryptographic secrets. The impact on availability is minimal as the vulnerability does not directly enable denial of service. Overall, the threat is moderate for organizations with affected hardware, especially where physical security is insufficient or devices are deployed in exposed environments.

1. Inventory and identify all devices using Silicon Labs Series 2 SoCs and associated modules implementing Curve25519 and Curve448 cryptographic operations. 2. Where possible, configure cryptographic operations to use ephemeral keys to minimize the number of cryptographic operations using the same key, reducing the attack surface for DPA. 3. Enhance physical security controls around devices to prevent attackers from gaining the proximity or access necessary to perform power analysis attacks. This includes tamper-evident seals, secure enclosures, and restricted access zones. 4. Monitor vendor communications closely for firmware or hardware updates that introduce DPA countermeasures or patches, and plan for timely deployment. 5. For new deployments, consider alternative hardware platforms or cryptographic implementations that include robust side-channel attack mitigations. 6. Implement network-level encryption and authentication layers to provide defense-in-depth, so that even if cryptographic keys at the device level are compromised, additional security controls limit exploitation. 7. Conduct regular security assessments and penetration tests focusing on physical and side-channel attack vectors to evaluate the effectiveness of mitigations. 8. Educate operational staff about the risks of side-channel attacks and the importance of physical security for embedded devices.