CVE-2025-26780 in Modem Exynos
Summary
by MITRE • 07/07/2025
An issue was discovered in L2 in Samsung Mobile Processor and Modem Exynos 2400 and Modem 5400. The lack of a length check leads to a Denial of Service via a malformed PDCP packet.
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Analysis
by VulDB Data Team • 10/27/2025
The vulnerability identified as CVE-2025-26780 represents a critical security flaw within the Samsung Exynos 2400 and Modem 5400 mobile processor systems. This issue specifically affects the Packet Data Convergence Protocol layer implementation, where insufficient input validation mechanisms fail to properly verify packet length parameters. The affected hardware components operate within mobile device architectures that process wireless communication protocols, making this vulnerability particularly concerning for mobile network security. The flaw exists in the modem processing units that handle packet data convergence protocol operations, which are essential for managing data transmission between mobile devices and network infrastructure.
The technical root cause of this vulnerability stems from the absence of proper length validation checks within the PDCP packet processing pipeline. When malformed PDCP packets are received by the affected Exynos processors, the system fails to validate the packet length fields before processing the data. This omission creates a condition where an attacker can craft specially malformed packets that exceed expected buffer sizes or violate protocol specifications. The lack of bounds checking allows the processor to attempt processing of invalid packet structures, leading to system instability and operational disruption. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, as the system fails to validate the legitimacy of packet length parameters before processing them. The vulnerability is classified as a buffer over-read condition that can trigger system-level failures.
The operational impact of CVE-2025-26780 extends beyond simple service interruption to potentially compromise the overall integrity of mobile communication systems. When exploited, this vulnerability can cause denial of service conditions that affect cellular connectivity, preventing users from making calls, sending messages, or accessing data services. The attack surface includes any mobile device running on the affected Exynos processors, making it a widespread concern across Samsung mobile platforms. Network operators may experience service degradation as affected devices become unresponsive to network communications, while individual users face complete loss of connectivity. The vulnerability can be exploited remotely through malicious packet injection attacks, making it particularly dangerous in environments where wireless communication is critical for operations. This type of attack aligns with ATT&CK technique T1499.004 for Network Denial of Service, which specifically addresses attacks targeting network infrastructure and device connectivity.
Mitigation strategies for this vulnerability require immediate firmware updates from Samsung to address the missing length validation checks within the PDCP processing modules. System administrators should implement network monitoring solutions that can detect and filter malformed PDCP packets before they reach affected devices. The implementation of input validation controls and enhanced packet filtering mechanisms can help prevent exploitation of this vulnerability. Organizations should also consider deploying network segmentation strategies to limit the potential impact of such attacks. Additionally, regular security assessments of mobile device firmware and modem components should be conducted to identify similar validation gaps. The fix should include comprehensive bounds checking for all packet length parameters and proper error handling mechanisms that gracefully reject malformed packets rather than allowing system crashes. This vulnerability demonstrates the critical importance of robust input validation in mobile communication systems and highlights the need for continuous security auditing of embedded processor components.