Introduction
Remote attackers can achieve code execution on millions of Snapdragon-powered devices without any user interaction. This vulnerability, CVE-2025-27034, is already being exploited in the wild and affects smartphones, IoT, and automotive systems globally.
Qualcomm is a dominant force in the mobile chipset industry, with its Snapdragon processors found in flagship phones, connected vehicles, and critical IoT infrastructure. The company's technology underpins much of the world's mobile communications, making vulnerabilities in its products highly impactful for both consumers and enterprises.
Technical Information
CVE-2025-27034 is a critical memory corruption vulnerability in Qualcomm's Multi-Mode Call Processor, specifically during the selection of a Public Land Mobile Network (PLMN) from the Steering of Roaming (SoR) failed list. The flaw is categorized under CWE-129 (Improper Validation of Array Index).
The vulnerability is triggered when the Multi-Mode Call Processor processes malformed PLMN selection responses from the SoR failed list. Insufficient validation of array indices allows out-of-bounds memory writes. An attacker who can send crafted PLMN selection messages to a vulnerable device can corrupt memory in the modem firmware, leading to remote code execution with elevated privileges. This attack does not require user interaction or authentication and can be performed remotely over network connections.
Affected code paths reside in proprietary Qualcomm modem firmware, making them difficult to audit or monitor by device vendors and end users. The vulnerability is present in multiple generations of Snapdragon chipsets, including those used in smartphones, IoT, and automotive systems. The issue is particularly severe because it affects the modem processor, which operates at a lower level than the main application processor, potentially bypassing many traditional security controls.
No public code snippets are available for this vulnerability. The technical root cause is improper bounds checking when parsing PLMN selection responses, which is a classic memory corruption vector in low-level firmware.
Patch Information
In the September 2025 Android Security Bulletin, a critical vulnerability in the System component was identified, potentially allowing remote code execution without user interaction. To address this, the Android Open Source Project (AOSP) implemented a patch that introduces additional validation checks within the affected module. This enhancement ensures that incoming data is properly sanitized, effectively mitigating the risk of unauthorized code execution. The patch has been integrated into AOSP versions 15 and 16, and users are strongly encouraged to update their devices to the 2025-09-05 security patch level or later to benefit from this fix.
Patch source: Android Security Bulletin September 2025
Detection Methods
Detecting exploitation of CVE-2025-27034, a critical memory corruption vulnerability in Qualcomm's Multi-Mode Call Processor, requires a multifaceted approach. (cybersixt.com)
Network Traffic Analysis:
Monitor for unusual network patterns, such as unexpected data transmissions or connections to known malicious IP addresses. Anomalies in network behavior can indicate exploitation attempts.
System Log Monitoring:
Regularly review system logs for signs of unauthorized access or abnormal system behavior. Indicators may include unexpected system crashes, reboots, or error messages related to memory access violations.
Behavioral Analysis:
Implement behavioral analysis tools to detect deviations from normal device operations. Sudden changes in device performance, unexplained battery drain, or unauthorized application installations can be signs of compromise.
Firmware Integrity Checks:
Utilize tools that verify the integrity of device firmware. Any unauthorized modifications or anomalies in firmware can indicate exploitation of vulnerabilities like CVE-2025-27034.
Security Information and Event Management (SIEM) Systems:
Deploy SIEM systems to aggregate and analyze security data across the network. These systems can correlate events and identify patterns indicative of exploitation attempts.
Regular Vulnerability Scanning:
Conduct regular vulnerability assessments to identify and remediate potential security gaps. Keeping systems updated with the latest security patches is crucial in mitigating risks associated with known vulnerabilities.
By integrating these detection methods, organizations can enhance their ability to identify and respond to potential exploitation of CVE-2025-27034, thereby strengthening their overall security posture.
Detection source: cybersixt.com
Affected Systems and Versions
CVE-2025-27034 affects the following Qualcomm products and versions (as identified in public advisories):
- Snapdragon 8 Gen1
- Snapdragon X55 5G Modem-RF Systems
- QCM5430
- FastConnect 7800
- Automotive modems including Snapdragon Auto 5G
- Other IoT and infrastructure chipsets as listed in the Qualcomm September 2025 Security Bulletin
The vulnerability is present in devices running unpatched firmware prior to the 2025-09-05 security patch level. Devices running AOSP versions prior to 15 or 16, or not updated to the 2025-09-05 patch level, remain vulnerable.
Vendor Security History
Qualcomm has a history of critical vulnerabilities in its modem and baseband components. Notably, CVE-2025-21483 was disclosed in the same security bulletin and also affected core communication modules with a similar CVSS score. The company has improved its patch response process, with regular security bulletins and coordinated disclosures, but recurring memory corruption issues indicate ongoing challenges in secure firmware development and testing.