CVE-2025-20763: Critical Privilege Escalation Risk in MediaTek mmdvfs

Overview

CVE-2025-20763 describes a potential security vulnerability within MediaTek’s mmdvfs component. This vulnerability stems from a missing bounds check that can lead to an out-of-bounds write. If successfully exploited by a malicious actor who has already gained System privilege, it could result in a local escalation of privilege. No user interaction is required for exploitation.

The issue is identified by MediaTek as Patch ID ALPS10267218 and Issue ID MSV-5032.

Technical Details

The vulnerability resides within the mmdvfs component and is triggered by a missing bounds check during a write operation. This oversight allows an attacker, having already achieved System privilege, to write data beyond the allocated buffer. The specific details of the affected code section are not publicly available without further reverse engineering or access to proprietary MediaTek documentation. However, the core problem is a lack of proper validation of input or calculated indices, leading to memory corruption.

CVSS Analysis

Due to the data provided, there is no CVSS score assigned to CVE-2025-20763. This could be for several reasons:

• The vulnerability is still being assessed.
• The impact is highly context-dependent and difficult to quantify without deeper analysis.
• MediaTek may have chosen not to publicly disclose the CVSS score for security reasons.

It’s important to note that the absence of a CVSS score doesn’t necessarily mean the vulnerability is low-risk. Given the potential for privilege escalation, it should be treated with appropriate concern.

Possible Impact

The potential impact of CVE-2025-20763 is significant:

• Local Privilege Escalation: An attacker with existing System privileges could leverage this vulnerability to gain higher-level privileges, potentially root access.
• System Compromise: Successful exploitation could lead to full system compromise, allowing the attacker to execute arbitrary code, install malware, or steal sensitive data.
• Device Control: With escalated privileges, an attacker could gain complete control over the affected device.

It’s crucial to emphasize that an attacker *must* already have System privilege to exploit this vulnerability. This likely implies a prior compromise or exploitation of another vulnerability.

Mitigation and Patch Steps

The primary mitigation strategy is to apply the patch provided by MediaTek. Follow these steps:

1. Check for Updates: Contact your device manufacturer or refer to their official website to check for available software updates.
2. Apply the Update: Install the update containing Patch ID ALPS10267218 (Issue ID MSV-5032) as soon as it becomes available. Follow the manufacturer’s instructions carefully during the update process.
3. Monitor Security Bulletins: Regularly monitor MediaTek’s product security bulletin and your device manufacturer’s security advisories for further information and updates.
4. Security Hardening (General): While not directly addressing CVE-2025-20763, implementing general security hardening measures can reduce the overall attack surface and minimize the likelihood of successful exploitation of other vulnerabilities. This includes keeping the OS and applications up-to-date, using strong passwords, and enabling security features.