CVE-2025-53179 is a heap-based buffer overflow vulnerability identified in the PDF preview module of Huawei's HarmonyOS versions 5.0.1 and 5.1.0. The vulnerability is classified under CWE-122, which involves improper management of memory buffers leading to potential overflow conditions. Specifically, this flaw arises from a null pointer dereference scenario within the PDF preview functionality, which can cause the application or system process handling PDF previews to behave unexpectedly or crash. While the vulnerability does not impact confidentiality or integrity directly, successful exploitation results in a denial of service by destabilizing the affected function, thereby impacting availability. The CVSS v3.1 base score is 6.5 (medium severity), with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The scope remains unchanged (S:U), and the impact is solely on availability (A:H), with no impact on confidentiality or integrity. There are no known exploits in the wild at the time of publication, and no patches have been released yet. This vulnerability could be triggered when a user previews a crafted malicious PDF file, causing the PDF preview module to dereference a null pointer and overflow a heap buffer, leading to a crash or denial of service. Given the nature of the vulnerability, it could be leveraged by attackers to disrupt device functionality or user experience but is unlikely to lead to remote code execution or data breaches without additional chained vulnerabilities.

For European organizations using Huawei devices running HarmonyOS 5.0.1 or 5.1.0, this vulnerability poses a risk primarily to system stability and availability. Enterprises relying on HarmonyOS-powered devices for critical operations, especially those that involve frequent handling or previewing of PDF documents, may experience service interruptions or device crashes if targeted by malicious PDF files. This could affect productivity and operational continuity, particularly in sectors where Huawei devices are integrated into communication or IoT infrastructures. Although the vulnerability does not compromise confidentiality or integrity, the denial of service impact could disrupt workflows and potentially cause downtime in environments where device availability is critical. Additionally, since exploitation requires user interaction (opening a malicious PDF), phishing or social engineering campaigns could be used to trigger the vulnerability, increasing the risk in environments with less stringent user awareness training. The absence of known exploits currently reduces immediate risk, but the medium severity score indicates that organizations should proactively address the issue to prevent future exploitation.

1. Immediate mitigation should focus on user awareness: educate users to avoid opening PDF files from untrusted or unknown sources, especially on HarmonyOS devices. 2. Implement network-level protections such as email and web filtering to block or quarantine suspicious PDF attachments or downloads. 3. Monitor device logs and behavior for signs of crashes or instability related to PDF preview operations to detect potential exploitation attempts early. 4. Since no patches are currently available, organizations should consider restricting or disabling the PDF preview functionality on HarmonyOS devices where feasible until a vendor patch is released. 5. Maintain up-to-date backups and ensure incident response plans include procedures for handling device unavailability caused by such vulnerabilities. 6. Engage with Huawei support channels to obtain timely updates on patch availability and apply security updates promptly once released. 7. For organizations with critical deployments, consider network segmentation or limiting the exposure of HarmonyOS devices to untrusted networks to reduce attack surface.