CVE-2025-2329 is a medium-severity vulnerability identified in Silicon Labs' OpenThread Radio Co-Processor (RCP) implementations, specifically affecting versions 2.5.0, 2.6.0, and an unspecified version labeled '0'. The vulnerability arises from improper handling of the SPI transmit buffer under high traffic conditions. When the OpenThread RCP operates in environments with heavy network traffic, it fails to clear the SPI transmit buffer properly before sending data to the host system. This results in the transmission of corrupted packets over the SPI interface. The host, upon receiving these malformed packets, resets the RCP to recover from the error state. This reset behavior leads to a denial of service (DoS) condition, as the RCP becomes temporarily unavailable for normal operation. The vulnerability is classified under CWE-908, which pertains to the use of uninitialized resources, indicating that the SPI transmit buffer is not properly initialized or cleared before use. The CVSS 4.0 base score is 5.3, reflecting a medium severity level. The attack vector is adjacent (AV:A), meaning exploitation requires local network proximity, but no privileges, user interaction, or authentication are necessary. The impact is primarily on availability (VA:L), with no direct confidentiality or integrity impact. No known exploits are currently reported in the wild, and no patches have been linked yet. This vulnerability affects embedded systems using Silicon Labs' OpenThread RCP, which is commonly deployed in IoT and wireless mesh networking devices that rely on Thread protocol for low-power, secure device communication.

For European organizations, the impact of CVE-2025-2329 can be significant in sectors relying on IoT infrastructure and wireless mesh networks, such as smart cities, industrial automation, healthcare, and building management systems. The denial of service caused by RCP resets can lead to intermittent or prolonged loss of connectivity between devices, disrupting critical operations and data flows. In environments where real-time monitoring or control is essential, such as manufacturing plants or energy grids, this disruption could degrade operational efficiency or safety. Additionally, the failure mode could complicate incident response and troubleshooting due to unexpected device resets. Although the vulnerability does not directly compromise data confidentiality or integrity, the availability impact could indirectly affect business continuity and service reliability. European organizations with deployments of Silicon Labs OpenThread-based devices should be aware that the vulnerability requires high traffic conditions to manifest, so networks with dense device populations or heavy communication loads are more at risk. The absence of known exploits reduces immediate threat but does not eliminate the risk, especially as attackers may develop exploits once the vulnerability becomes widely known.

To mitigate CVE-2025-2329, European organizations should implement several specific measures beyond generic best practices: 1) Monitor network traffic patterns to identify and limit excessive SPI communication bursts that could trigger the vulnerability. Implement rate limiting or traffic shaping at the device or network level to prevent high traffic conditions that cause buffer corruption. 2) Where possible, update OpenThread RCP firmware to versions that address this issue once Silicon Labs releases patches. Until patches are available, consider deploying compensating controls such as watchdog timers or automated device recovery mechanisms to minimize downtime from RCP resets. 3) Conduct thorough testing of IoT deployments under simulated high traffic loads to detect potential instability or DoS symptoms related to this vulnerability. 4) Segment IoT networks to isolate critical systems from less trusted or high-traffic zones, reducing the likelihood of widespread impact. 5) Engage with device vendors and integrators to confirm the presence of this vulnerability and coordinate timely remediation. 6) Maintain robust incident detection capabilities to quickly identify and respond to device resets or communication failures indicative of exploitation attempts. These targeted actions will help reduce the risk and operational impact of this vulnerability in real-world deployments.