CVE-2026-35495 in Exynos 1080
Summary
by MITRE • 11/05/2026
In IMS stack, improper handling of SIP packets leads to Incorrect_Access_Control vulnerability
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Analysis
by VulDB Data Team • 11/05/2026
The Internet Protocol Multimedia Subsystem serves as the foundational architecture for delivering multimedia services over IP networks, relying heavily on the Session Initiation Protocol for signaling and session management. Within this complex ecosystem, the integrity of access control mechanisms is paramount to preventing unauthorized usage and ensuring service quality. A critical vulnerability has been identified in certain IMS implementations where the stack exhibits improper handling of SIP packets, resulting in an Incorrect Access Control flaw. This defect fundamentally undermines the security boundaries established by network operators, allowing attackers to bypass authentication or authorization checks that are designed to restrict access based on user identity, subscription status, or service entitlements.
The technical root cause lies in how specific SIP message fields are parsed and validated during the session establishment phase. In a properly secured implementation, every incoming request must be rigorously checked against policy decision points before any resources are allocated or state is maintained. However, due to logic errors or insufficient validation routines within the vulnerable stack, certain malformed or specially crafted SIP packets can exploit gaps in this verification process. For instance, an attacker might manipulate headers such as Via, Route, or P-Asserted-Identity to confuse the parser into accepting a request from an unauthenticated source or one that lacks necessary permissions. This misalignment between expected protocol behavior and actual implementation allows for privilege escalation within the signaling plane, effectively granting the attacker capabilities reserved for legitimate subscribers or higher-level administrators.
From an operational perspective, this vulnerability poses severe risks to both service providers and end-users. Successful exploitation can lead to unauthorized access to premium services, resulting in direct financial loss through billing fraud where attackers consume resources without paying. Furthermore, it enables denial of service attacks by allowing malicious actors to exhaust system resources or disrupt ongoing sessions for legitimate users. The ability to bypass access controls also facilitates eavesdropping and man-in-the-middle scenarios if the compromised session setup leads to insecure media path establishment. In enterprise environments relying on IMS for unified communications, this could expose sensitive corporate conversations and data to interception by unauthorized parties, violating confidentiality requirements mandated by various regulatory frameworks.
This flaw aligns with CWE-284 Improper Access Control, as it represents a failure in the system's ability to restrict actions or information access to authorized users. Additionally, from an offensive security perspective, this vulnerability maps closely to MITRE ATT&CK techniques related to Initial Access and Privilege Escalation within networked environments. Attackers can leverage these weaknesses to establish a foothold deep inside the carrier infrastructure, potentially using it as a pivot point for further lateral movement toward core database systems or other critical backend services that are typically isolated from direct external access.
Mitigation strategies must focus on hardening the SIP stack and enhancing input validation mechanisms. Vendors should immediately apply patches that correct the parsing logic to ensure strict adherence to RFC 3261 standards and enforce rigorous checks on all SIP headers before processing. Network operators can implement temporary compensating controls by deploying Session Border Controllers configured with deep packet inspection capabilities capable of detecting anomalous SIP traffic patterns associated with this exploit. Regular security audits, fuzz testing of the signaling interface, and continuous monitoring for unusual access attempts are essential to maintain resilience against such vulnerabilities until permanent code fixes are deployed across all affected network elements.