CVE-2025-27840: Vulnerability Exploitation in Espressif ESP32 Bluetooth Chips Can Lead to Unauthorized Access to Devices
Following the disclosure of an authorization bypass vulnerability in the Motorola Mobility Droid Razr HD (Model XT926), another major security flaw in a widely used product now threatens global organizations with unauthorized access and potential control over critical systems.
The ESP32 microchip by Espressif, found in over 1 billion devices as of 2023, contains 29 undocumented HCI (Host Controller Interface) commands that pose security risks. The uncovered vulnerability, tracked as CVE-2025-27840, affects ESP32 Bluetooth chips and can potentially lead to attacks such as device spoofing, unauthorized data access, network pivoting, and persistent threats. Exploiting these hidden commands could compromise device integrity, risking unauthorized control over critical systems.
With the growing surge of vulnerabilities in widely used software and their rapid exploitation in real-world attacks, the demand for proactive threat detection has never been more critical. In just the first two months of 2025, NIST has identified over 9,000 vulnerabilities, many of which are already posing significant challenges for SOC teams worldwide. As cyber threats become more sophisticated, security teams must focus on early detection strategies to outpace attackers and mitigate risks before they escalate.
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CVE-2025-27840 Analysis
CVE-2025-27840 is a medium-severity vulnerability with a CVSS score of 6.8 that impacts Espressif ESP32 Bluetooth chips widely integrated into IoT devices. These chips support both Bluetooth and Wi-Fi connectivity, making them a key component in smart technology.
The flaw stems from 29 undocumented HCI commands. If exploited, CVE-2025-27840 could compromise device integrity and security, exposing organizations to unauthorized access and potential control over critical systems. One particularly concerning command, 0xFC02, allows direct memory writing on the device. The existence of these undocumented commands introduces serious security implications, as they could enable covert operations that bypass conventional security measures.
Apart from enabling unauthorized access, CVE-2025-27840 could give attackers the green light to modify or corrupt stored data, threatening the accuracy and reliability of essential operational information in connected systems. Moreover, this vulnerability puts IoT devices at risk of being compromised, posing significant threats to organizations that rely on these devices—particularly in industry verticals where security and data integrity are vital—thereby undermining the organization’s overall security posture.
The flaw impacts the ESP32 2025-03-06 product version. The availability of a PoC code, developed by security researchers, shows how the vulnerability can be leveraged in real-world data breaches and serves as a crucial element for its exploitation, potentially leading to ransomware attacks. Although the vendor considers the risk to be low, it has announced plans to release a software fix to remove the related undocumented commands as a potential CVE-2025-27840 mitigation measure. Organizations striving to risk-optimize their cybersecurity posture, can rely on SOC Prime Platform for collective cyber defense to timely identify CVE exploitation attempts and proactively thwart cyber attacks of any scale and sophistication.
