CVE-2025-55297 is a medium-severity vulnerability classified under CWE-120 (Classic Buffer Overflow) and CWE-131 (Incorrect Calculation of Buffer Size) affecting the Espressif Internet of Things Development Framework (ESP-IDF). Specifically, the BluFi example within ESP-IDF contains memory overflow vulnerabilities in two critical areas: Wi-Fi credential handling and the Diffie–Hellman key exchange process. These buffer overflows occur due to improper validation of input sizes before copying data into fixed-size buffers, which can lead to memory corruption. Exploiting these vulnerabilities could allow an attacker to execute arbitrary code, cause denial of service, or compromise the confidentiality and integrity of cryptographic operations. The affected versions include all ESP-IDF releases prior to 5.0.9, and certain beta and minor releases up to 5.4.1, with fixes incorporated in versions 5.4.1, 5.3.3, 5.1.6, and 5.0.9. The CVSS 4.0 score is 5.2, indicating a medium severity level, with attack vector being adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild. The vulnerability poses a significant risk to IoT devices using ESP-IDF, especially those relying on BluFi for Wi-Fi provisioning and secure key exchange, potentially enabling attackers to compromise device security remotely within the local network or via Bluetooth interfaces.

For European organizations deploying IoT devices based on Espressif ESP-IDF, this vulnerability could lead to unauthorized access to sensitive Wi-Fi credentials and cryptographic keys, undermining device security and network integrity. Critical infrastructure sectors such as manufacturing, smart city deployments, healthcare, and energy that utilize Espressif-based IoT devices for automation and monitoring may face risks of service disruption, data breaches, or lateral movement by attackers. The buffer overflow could be exploited to execute arbitrary code, potentially allowing attackers to implant persistent malware or disrupt device operations, impacting availability. Given the widespread adoption of Espressif chips in consumer and industrial IoT devices, the vulnerability could affect a broad range of endpoints, increasing the attack surface. The absence of required privileges and user interaction lowers the barrier for exploitation within local or Bluetooth-adjacent environments, raising concerns for environments with dense IoT deployments. However, the lack of known exploits in the wild suggests that immediate widespread attacks are not yet observed, but proactive patching is critical to prevent future exploitation.

European organizations should prioritize upgrading ESP-IDF to the fixed versions 5.4.1, 5.3.3, 5.1.6, or 5.0.9 as applicable to their deployment. For devices where immediate firmware updates are not feasible, network segmentation should be enforced to isolate vulnerable IoT devices from critical network segments and limit Bluetooth and Wi-Fi access to trusted sources only. Implement strict access controls and monitoring for anomalous Bluetooth and Wi-Fi provisioning activities. Employ runtime protections such as stack canaries and address space layout randomization (ASLR) where supported by the device firmware. Conduct thorough code audits and fuzz testing on custom implementations of Wi-Fi credential handling and cryptographic key exchanges to detect similar buffer overflow issues. Additionally, maintain an inventory of Espressif-based devices to assess exposure and prioritize patching. Collaborate with device vendors to ensure timely firmware updates and validate that patches address the vulnerability comprehensively. Finally, integrate this vulnerability into vulnerability management and incident response plans to enable rapid detection and remediation.