This article provides a detailed analysis of CVE-2025-40220, a vulnerability found in the Linux kernel’s fuse (Filesystem in Userspace) implementation. This issue can lead to a livelock situation, particularly when using fuseblk workers. We’ll explore the technical details, potential impact, and steps to mitigate this vulnerability. Overview CVE-2025-40220 identifies a flaw in the way the Linux kernel handles file puts within the fuse subsystem, specifically when dealing with asynchronous I/O (AIO) operations in conjunction with fuseblk. This can result in a scenario where fuse server threads become stuck waiting for responses from themselves, effectively halting operations. Technical Details The vulnerability…

A critical race condition vulnerability, identified as CVE-2025-40219, has been discovered and resolved in the Linux kernel’s PCI/IOV (Input/Output Virtualization) Single Root I/O Virtualization (SR-IOV) implementation. This flaw could lead to double remove and list corruption, particularly affecting systems running on the s390 architecture. Overview CVE-2025-40219 stems from a lack of proper locking mechanisms during the enabling and disabling of SR-IOV virtual functions (VFs). Specifically, when disabling SR-IOV through config space accesses to the parent Physical Function (PF), the `sriov_disable()` function removes PCI devices representing the VFs. The absence of the `pci_rescan_remove_lock` during this process allows for concurrent removal and…

Overview CVE-2025-40218 describes a vulnerability in the Linux kernel’s DAMON (Data Access Monitoring) subsystem. Specifically, the issue resided in the virtual address space operation set implementation (vaddr) of DAMON. An infinite loop could occur during page table walks when `pte_offset_map_lock()` continuously failed due to a pmd migration entry. This could lead to a soft lockup, particularly when CPU hotplugging and DAMON were running concurrently. A patch has been implemented to prevent this infinite loop by avoiding retries of the page table walk in case of failure. Technical Details The DAMON vaddr implementation uses `pte_offset_map_lock()` to read and write page table…

Overview CVE-2025-40217 addresses a security enhancement in the Linux kernel related to the PID file system (PIDFS). This update focuses on implementing stricter validation of extensible ioctls (input/output control) operations performed within the PIDFS environment. The goal is to improve the overall security posture of the kernel by mitigating potential risks associated with improperly handled or maliciously crafted ioctl calls. Technical Details The vulnerability lies in the potential for insufficient validation of parameters passed to extensible ioctl commands when interacting with PIDFS. PIDFS provides a filesystem interface for accessing process ID (PID) information. Extensible ioctls allow for custom operations to…

Overview CVE-2025-40216 describes a vulnerability in the Linux kernel related to the io_uring subsystem. Specifically, it addresses an issue where the kernel incorrectly assumed a guaranteed alignment for user-provided virtual addresses. This could lead to unexpected behavior or potential security implications. This vulnerability has been resolved in recent kernel updates. This blog post will detail the technical aspects of the vulnerability, its potential impact, and the necessary mitigation steps. Technical Details The io_uring subsystem in the Linux kernel is designed for high-performance asynchronous I/O operations. The vulnerability arises from how the kernel calculates an offset into a folio (a unit…

Overview CVE-2025-2848 is a medium-severity vulnerability affecting Synology Mail Server. Successful exploitation could allow a remote, authenticated attacker to read and write non-sensitive configuration settings and disable certain non-critical functions within the Mail Server application. This vulnerability highlights the importance of proper access control and input validation, even for authenticated users. While the impact is limited to non-sensitive settings and non-critical functions, it could still be leveraged to disrupt service or gather information for further attacks. Technical Details The specific technical details of the vulnerability are not publicly available beyond the general description provided by Synology. However, the ability to…

Overview CVE-2025-29846 is a high-severity information disclosure vulnerability found in the `portenable` CGI application. This flaw allows remote, authenticated users to obtain the status of installed packages on the affected system. Successful exploitation could provide attackers with valuable information to aid in further attacks. Technical Details The vulnerability resides within the `portenable` CGI component. It occurs because the application fails to properly restrict access to information regarding installed packages. An authenticated attacker can leverage this vulnerability to query the system and retrieve a list of installed software, including version numbers and configuration details. Specific exploitation vectors involve crafted HTTP requests…

Overview CVE-2025-29845 is a medium-severity vulnerability affecting VideoPlayer2. This flaw allows remote, authenticated users to potentially read sensitive subtitle files (.srt) without proper authorization. This can lead to the exposure of information embedded within the subtitles, which could include dialogue, translations, and even embedded scripts or notes, depending on the use case. Technical Details The vulnerability resides within the subtitle handling CGI script of VideoPlayer2. It’s believed that insufficient access control checks are performed before allowing a user to retrieve a requested .srt file. By crafting a specific request, an authenticated user can bypass the intended file access restrictions and…

Overview CVE-2025-29844 is a medium severity vulnerability affecting Synology FileStation. This vulnerability allows a remote, authenticated user to read file metadata and path information that they should not normally have access to. This information leak could be leveraged for further attacks or to gain unauthorized knowledge of the NAS file structure. Technical Details The vulnerability resides within the FileStation’s CGI (Common Gateway Interface) component. Improper input validation and insufficient access control checks within the CGI script allow an attacker with valid login credentials to craft specific requests that bypass intended security mechanisms. By exploiting this, a user can obtain sensitive…

Overview CVE-2025-29843 describes a medium-severity vulnerability affecting Synology FileStation. This flaw allows remote, authenticated users to potentially read and write image files on the system. The vulnerability stems from an issue within the thumb cgi component of FileStation. Technical Details The vulnerability lies within the `thumb.cgi` application of Synology FileStation. Due to insufficient input validation and authorization checks, a remote attacker with valid user credentials can manipulate requests to `thumb.cgi` to access or modify image files beyond their intended permissions. The specifics of the exploit depend on the vulnerable version of FileStation, but generally involve crafting malicious requests that bypass…