CVE-2026-33972 in Exynos 1080
Summary
by MITRE • 11/05/2026
In the Exynos modem's IMS stack, Out of Bound access occurs due to improper validation.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 11/05/2026
The vulnerability identified within the Internet Protocol Multimedia Subsystem (IMS) stack of Samsung Exynos modems represents a critical security flaw rooted in insufficient input validation mechanisms. The IMS protocol is fundamental for enabling Voice over LTE and other multimedia services on modern mobile devices, handling session initiation, modification, and termination through complex signaling messages. When an attacker crafts maliciously formatted SIP or SDP packets that are processed by the modem's firmware, the lack of rigorous boundary checks allows data to be read from memory locations outside the intended buffer limits. This out-of-bounds access is not merely a theoretical risk but a direct consequence of improper validation logic within the parsing routines responsible for interpreting these signaling messages.
From a technical perspective, this flaw aligns with CWE-125, which describes Out-of-Bounds Read vulnerabilities where software reads data past the end or before the beginning of the intended buffer. In the context of mobile modem firmware, such errors often occur during the processing of variable-length fields in protocol headers. If the code fails to verify that the length field does not exceed the allocated memory space for a specific structure, it may retrieve sensitive information from adjacent memory regions. This can lead to the leakage of internal state variables, cryptographic keys, or other privileged data stored in the modem's memory space. The severity is compounded by the fact that modems operate with high privileges and are often exposed to untrusted networks via radio interfaces, making them a prime target for remote exploitation attempts.
The operational impact of this vulnerability extends beyond simple information disclosure. Depending on how the out-of-bounds read interacts with subsequent code execution paths or error handling routines, it could potentially lead to denial of service conditions by causing crashes in critical modem subsystems. Furthermore, if the leaked data includes session keys or authentication tokens, an attacker could perform man-in-the-middle attacks to intercept voice calls or SMS messages. This undermines the confidentiality and integrity guarantees provided by LTE security mechanisms such as EPS-AKA. The vulnerability also impacts user privacy significantly, as IMS stacks often handle personal communication metadata that must remain isolated from potential network-based adversaries.
Mitigation strategies for this issue primarily involve vendor-side firmware updates that implement strict bounds checking in all parsing functions within the IMS stack. Developers should enforce rigorous validation of message lengths and offsets before any memory access operations are performed. Additionally, employing static analysis tools during the development phase can help identify similar logic errors across the codebase. For end-users, ensuring that device firmware is updated to the latest version provided by Samsung or their carrier is essential to patch this specific flaw. Network operators may also implement deep packet inspection at the network edge to filter out malformed SIP messages before they reach vulnerable devices, providing a layer of defense-in-depth against exploitation attempts targeting these protocol parsing vulnerabilities.