CVE-2026-20501 in MT2718
Summary
by MITRE • 09/07/2026
In vdec, there is a possible out of bounds write due to a heap buffer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11262030; Issue ID: MSV-9197.
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Analysis
by VulDB Data Team • 09/07/2026
The vulnerability identified under issue identifier MSV-9197 and addressed by patch ALPS11262030 resides within the vdec component, which is typically responsible for video decoding operations in embedded systems or mobile platforms. This specific flaw manifests as a heap buffer overflow that results in an out-of-bounds write operation. In software architecture, particularly in media processing pipelines like video decoders, memory allocation on the heap is dynamic and frequent due to the variable size of encoded video frames. When the vdec component fails to properly validate input data lengths against allocated buffer sizes during the decoding process, it permits writing beyond the boundaries of the intended memory region. This lack of rigorous bounds checking allows an attacker or maliciously crafted media file to overwrite adjacent heap metadata or other critical data structures stored in contiguous memory locations.
From a technical perspective, this flaw is classified under CWE-122, which denotes Heap-based Buffer Overflow. The core issue lies in the absence of sufficient validation checks before performing write operations on dynamically allocated memory blocks. When an oversized frame header or payload is processed, the decoder calculates incorrect offsets or fails to account for padding and alignment requirements correctly. Consequently, data intended for one buffer spills over into neighboring allocations. This corruption can alter control flow by modifying function pointers stored in heap metadata structures such as malloc headers or free lists. If these overwritten values are later dereferenced during memory deallocation or subsequent allocation requests, the attacker gains arbitrary code execution capabilities within the context of the vdec process.
The operational impact of this vulnerability is severe due to its potential for local privilege escalation. Since video decoding services often run with elevated privileges to access hardware acceleration features and low-level system resources, compromising the integrity of these processes can lead to a complete takeover of the underlying operating system. The description notes that no additional execution privileges are required for exploitation, meaning an unprivileged user or application can trigger this flaw simply by providing malicious input data. Furthermore, the requirement for user interaction is absent in many automated scenarios; if the vdec service automatically processes media files from network sources, removable storage, or background applications, the attack vector becomes remote and passive. This significantly lowers the barrier to entry for attackers seeking to compromise device integrity.
In terms of threat modeling, this vulnerability aligns with MITRE ATT&CK techniques related to initial access via malicious content and subsequent privilege escalation through memory corruption exploits. The ability to execute code locally without user interaction places it in a high-risk category within security assessment frameworks. Attackers can leverage the heap overflow to bypass standard security mitigations such as stack canaries or non-executable memory pages, depending on how the heap layout is manipulated. By carefully crafting the payload to overwrite specific pointers, an attacker can redirect execution flow to shellcode injected into other writable regions of memory, effectively achieving arbitrary code execution with the privileges held by the vdec service.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. The primary remediation is the application of Patch ID ALPS11262030, which presumably introduces stricter input validation and bounds checking within the video decoding logic. Developers should ensure that all buffer sizes are explicitly verified against available memory before any write operations occur. Additionally, implementing defensive programming practices such as using safe string handling functions and enabling compiler-based security features like AddressSanitizer during development can help detect similar issues early in the lifecycle. For deployed systems, deploying runtime application self-protection mechanisms or strict sandboxing policies for media processing services can limit the blast radius of any successful exploitation attempt by restricting access to critical system resources.