CVE-2026-20491 in MT2735
Summary
by MITRE • 08/03/2026
In med, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local denial of service with User execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS10981478 (Note: For MT6890, MT6990, MT6988) / AUTO00851173 (Note: For MT2735, MT2737); Issue ID: MSV-7652.
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Analysis
by VulDB Data Team • 08/03/2026
This vulnerability represents a critical out-of-bounds write condition that occurs within the media processing subsystem of specific MediaTek chipsets including MT6890, MT6990, MT6988, MT2735, and MT2737. The flaw stems from an inadequate bounds checking mechanism during media data processing operations, where the system fails to properly validate input parameters before writing data to memory locations. This improper validation creates a scenario where maliciously crafted media content can trigger memory corruption beyond intended boundaries, potentially leading to system instability or complete denial of service conditions.
The technical implementation of this vulnerability exposes a fundamental flaw in the memory management protocols of the affected media processing units. When processing multimedia files or streams, the system performs insufficient boundary verification on buffer sizes and data offsets, allowing an attacker to manipulate input parameters that control memory allocation and writing operations. This condition falls under the CWE-129 category of "Improper Validation of Array Index" and represents a variant of heap-based buffer overflow conditions. The vulnerability is particularly concerning because it requires only user execution privileges for exploitation, eliminating the need for elevated access rights or complex attack vectors.
The operational impact of this vulnerability manifests primarily as local denial of service scenarios where legitimate media processing operations become disrupted. An attacker can craft malicious media files or streams that when processed by the affected system will trigger the out-of-bounds write condition, causing the media processing subsystem to crash or behave unpredictably. This disruption affects multimedia applications including video playback, audio processing, and image rendering capabilities on devices utilizing the vulnerable MediaTek chipsets. The vulnerability's exploitation does not require user interaction, making it particularly dangerous as it can be triggered automatically during normal media processing operations without any explicit user engagement.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1499.004 for Endpoint Denial of Service, representing both the exploitation vector and impact characteristics. The patch identifiers ALPS10981478 and AUTO00851173 indicate that MediaTek has provided specific firmware updates addressing this issue through improved bounds checking implementations and enhanced input validation mechanisms. These patches typically involve strengthening memory management routines to properly validate all buffer access operations and implementing additional safeguards against malformed media data inputs. Organizations should prioritize applying these patches immediately, particularly in environments where multimedia processing is critical, as the vulnerability represents a significant risk to system availability and stability.
The broader implications extend beyond simple denial of service scenarios, as memory corruption vulnerabilities often serve as entry points for more sophisticated attacks or can be chained with other exploits to achieve privilege escalation. Security teams should monitor for potential exploitation attempts targeting this vulnerability in their networks, particularly in environments where media processing capabilities are exposed to untrusted content sources. The vulnerability underscores the importance of robust input validation and proper bounds checking in embedded systems and mobile device processors, where resource constraints often lead to overly aggressive optimization that can introduce security flaws.