CVE-2025-21423 is a vulnerability identified in multiple Qualcomm Snapdragon platforms and related components, stemming from improper validation of array indices (CWE-129) during processing of client calls to the EnableTestMode function via an Escape call interface. This improper validation leads to memory corruption, which can be exploited to achieve arbitrary code execution or cause system instability and denial of service. The vulnerability affects a wide range of Qualcomm products including various FastConnect modules (6200 through 7800 series), Snapdragon compute platforms (7c, 8c, 8cx series), and audio components (WCD and WSA series). The flaw requires an attacker to have local privileges (low-level privileges) but does not require user interaction, making it a potent threat in environments where multiple users or processes operate on the same device. The vulnerability was reserved in December 2024 and published in April 2025, with no known exploits reported in the wild to date. The CVSS v3.1 score of 7.8 indicates a high severity, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and privileges required. The root cause is a failure to properly validate array indices, which is a common programming error leading to out-of-bounds memory access and corruption. This can allow attackers to manipulate memory contents, potentially leading to privilege escalation or arbitrary code execution within the affected device's operating environment. Due to the broad range of affected Qualcomm hardware, this vulnerability poses a significant risk to mobile devices, laptops, and IoT devices that incorporate these chipsets.

The impact of CVE-2025-21423 is substantial for organizations worldwide that deploy devices powered by affected Qualcomm Snapdragon platforms. Successful exploitation can lead to arbitrary code execution, allowing attackers to escalate privileges, install persistent malware, or disrupt device functionality through denial of service. This compromises confidentiality, integrity, and availability of affected systems. Given the prevalence of Snapdragon chipsets in smartphones, tablets, laptops, and IoT devices, the vulnerability could be leveraged to target enterprise mobile endpoints, edge devices, and consumer electronics. Attackers with local access—such as malicious insiders, compromised applications, or malware—could exploit this flaw to gain deeper control over devices, bypass security controls, or exfiltrate sensitive data. The lack of required user interaction increases the risk in multi-user or shared device scenarios. Although no known exploits are currently reported, the high severity and broad device impact necessitate urgent attention to prevent potential future attacks. The vulnerability could also affect supply chain security and device integrity in critical infrastructure sectors relying on Qualcomm hardware.

To mitigate CVE-2025-21423, organizations should implement the following specific measures: 1) Monitor Qualcomm and device vendors for official patches or firmware updates addressing this vulnerability and apply them promptly across all affected devices. 2) Restrict local access to devices by enforcing strict user privilege separation and limiting administrative or debug capabilities to trusted personnel only. 3) Employ application whitelisting and endpoint protection solutions to detect and prevent unauthorized attempts to invoke EnableTestMode or related Escape calls. 4) Conduct regular security audits and vulnerability assessments on devices incorporating affected Qualcomm components to identify potential exploitation attempts. 5) For environments where patching is delayed, consider disabling or restricting access to debugging or test mode interfaces if feasible, to reduce attack surface. 6) Enhance monitoring and logging on devices to detect anomalous behavior indicative of exploitation attempts, such as unexpected memory corruption or abnormal process activity. 7) Educate users and administrators about the risks of local privilege escalation vulnerabilities and enforce strong physical security controls to prevent unauthorized device access. These targeted actions go beyond generic advice by focusing on controlling access to vulnerable interfaces and ensuring rapid deployment of vendor fixes.