CVE-2025-26780 is a high-severity vulnerability affecting the Layer 2 (L2) protocol implementation in Samsung Mobile Processor and Modem Exynos 2400 and Modem 5400 chipsets. The vulnerability arises due to the lack of proper length validation on incoming Packet Data Convergence Protocol (PDCP) packets. PDCP is a critical protocol layer in mobile communications responsible for header compression, ciphering, and integrity protection of data between the radio and core network. The absence of length checks allows an attacker to craft malformed PDCP packets that can trigger a Denial of Service (DoS) condition by causing the affected modem or processor to malfunction or crash. This vulnerability does not require any privileges or user interaction to exploit and can be triggered remotely over the network, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact is limited to availability, with no direct confidentiality or integrity compromise. The vulnerability is classified under CWE-20 (Improper Input Validation), highlighting the failure to validate input data properly. No patches or known exploits are currently reported, but the high CVSS score (7.5) reflects the significant risk of service disruption in mobile devices using these chipsets. Given the widespread use of Samsung Exynos processors in various mobile devices, this vulnerability could affect a large number of users and services relying on stable mobile connectivity.

For European organizations, the impact of CVE-2025-26780 could be substantial, especially for enterprises and service providers relying on mobile communications infrastructure that incorporates Samsung Exynos 2400 or 5400 modems. A successful DoS attack could disrupt mobile data connectivity, affecting critical business operations such as remote work, mobile transactions, and IoT device communications. Telecommunications providers using these chipsets in their network equipment or customer devices may face service outages, leading to customer dissatisfaction and potential regulatory scrutiny under EU digital service regulations. Additionally, sectors dependent on mobile broadband for operational continuity, including logistics, healthcare, and emergency services, could experience degraded service quality or interruptions. Although the vulnerability does not compromise data confidentiality or integrity, the availability impact alone can cause significant operational and financial damage. The lack of known exploits currently reduces immediate risk, but the ease of exploitation and remote attack vector necessitate proactive mitigation.

To mitigate CVE-2025-26780 effectively, European organizations should: 1) Monitor Samsung and device manufacturers for official firmware or software patches addressing this vulnerability and apply them promptly once available. 2) Engage with mobile device vendors and network equipment providers to verify the presence of affected chipsets and confirm patch deployment status. 3) Implement network-level protections such as anomaly detection systems to identify and block malformed PDCP packets or unusual traffic patterns targeting mobile infrastructure. 4) For critical mobile-dependent services, consider fallback communication channels or redundancy to maintain availability during potential DoS incidents. 5) Collaborate with mobile network operators to ensure robust incident response plans are in place for rapid mitigation of service disruptions. 6) Educate IT and security teams about the vulnerability specifics to enhance monitoring and response capabilities. Since no patches are currently available, temporary mitigations may include limiting exposure of vulnerable devices to untrusted networks or applying network segmentation to isolate critical mobile infrastructure components.