Overview CVE-2025-40242 describes a race condition vulnerability identified and resolved in the Linux kernel’s GFS2 file system. The vulnerability exists within the gdlm_put_lock() function. This flaw could potentially lead to a denial-of-service (DoS) situation due to dereferencing freed memory. This article provides a detailed analysis of the vulnerability, its potential impact, and mitigation steps. Technical Details The vulnerability lies within the gdlm_put_lock() function in the GFS2 file system. A small window of time exists where the DFL_UNMOUNT flag has been set, indicating an impending unmount, but the lockspace hasn’t actually been released yet. During this brief period, the Distributed Lock…

Overview CVE-2025-40241 describes a vulnerability found in the EROFS (Enhanced Read-Only File System) implementation within the Linux kernel. This flaw, discovered and reported by Robert, stems from improperly handled encoded extents in crafted, potentially corrupted, EROFS images. Successfully exploiting this vulnerability could lead to system crashes. Technical Details The vulnerability centers around two specific issues within the handling of encoded extents introduced in Linux kernel version 6.15: Invalid plen value: The first issue arises when the `plen` (physical length) field of an encoded extent has a non-zero value (e.g., 0x2000000) but does not conform to the expected format as defined…

Overview CVE-2025-40240 describes a NULL dereference vulnerability found and resolved in the Linux kernel’s Stream Control Transmission Protocol (SCTP) implementation. This vulnerability could potentially lead to a denial-of-service (DoS) condition if triggered. The flaw resides in how the kernel handles missing data buffers within SCTP chunks. Technical Details The vulnerability stems from a scenario where the chunk->skb pointer, which is expected to point to a socket buffer containing data for an SCTP chunk, could be unexpectedly NULL within a specific code block. The code was attempting to dereference this potentially NULL pointer, leading to a crash. Specifically, the vulnerability occurs…

Overview CVE-2025-40239 describes a critical vulnerability affecting the LAN8814 PHY driver within the Linux kernel. This vulnerability, if unaddressed, can lead to a null pointer dereference, potentially causing a kernel crash and system instability. The patch resolves the issue by ensuring the shared->phydev pointer is always initialized, regardless of PTP clock setup success. Technical Details The root cause of the vulnerability lies within the LAN8814 PTP probe function. Previously, the shared->phydev member was only set if the PTP clock was successfully configured. However, the lan8814_gpio_process_cap function, executed during IRQ handling, unconditionally accesses shared->phydev. If the PTP clock configuration failed, shared->phydev…

Overview CVE-2025-40238 describes a vulnerability in the Linux kernel related to the Mellanox mlx5 driver. This flaw specifically impacts the proper cleanup of IPsec configurations when using Mellanox MPV (Multi-Port Virtualization) devices. Failure to properly handle the cleanup process could lead to a kernel panic, resulting in a denial-of-service condition. This article provides a detailed technical analysis of the vulnerability, its potential impact, and recommended mitigation steps. Technical Details The vulnerability occurs during the detachment of a network device (netdev) using the mlx5e_detach_netdev() function. This process disables blocking events notifier, including IPsec MPV events between the InfiniBand (IB) subsystem and…

Overview CVE-2025-40237 describes a race condition vulnerability in the Linux kernel’s OverlayFS (overlay filesystem) implementation. Specifically, a NULL pointer dereference can occur during the unmount process of an OverlayFS filesystem when a file descriptor (fd) watching an overlayfs inode is accessed by inotify_fdinfo(). This vulnerability can lead to a system crash or other unpredictable behavior. Technical Details The vulnerability arises from a race condition between the filesystem unmount process and the inotify_fdinfo() function. Here’s a breakdown of the issue: When an OverlayFS filesystem is unmounted, the generic_shutdown_super() function is called. This function eventually sets the superblock’s root directory (sb->s_root) to…

Overview CVE-2025-40236 is a security vulnerability discovered and patched in the Linux kernel’s virtio-net subsystem. This flaw could potentially lead to an information leak when using GSO tunnels due to improper initialization of tunnel metadata. While the severity is not critical and has no CVSS score, understanding the issue and applying the fix is essential for maintaining a secure system. Technical Details The vulnerability stems from the virtio_net_hdr_tnl_from_skb() function. When a Generic Segmentation Offload (GSO) tunnel is negotiated, this function attempts to initialize tunnel metadata. However, it was found that the function failed to zero out unused receive hash (rxhash)…

Overview CVE-2025-40235 describes a vulnerability in the Btrfs filesystem implementation within the Linux kernel. This flaw can potentially lead to a NULL pointer dereference, resulting in a kernel panic and system crash. The vulnerability stems from improper error handling during the initialization of the Btrfs filesystem’s internal data structures. Specifically, if memory allocation fails during the initial setup, a cleanup routine attempts to access uninitialized memory, triggering the NULL pointer dereference. Technical Details The vulnerability resides in the btrfs_check_leaked_roots() function within the fs/btrfs/disk-io.c file. The issue occurs when either fs_info->super_copy or fs_info->super_for_commit fail to allocate memory within the btrfs_get_tree_subvol() function.…

Overview CVE-2025-40234 describes a vulnerability in the Linux kernel, specifically within the `alienware-wmi-wmax` driver. This driver is responsible for handling WMI (Windows Management Instrumentation) events on Alienware laptops. The vulnerability arises from a potential NULL pointer dereference in the driver’s sleep handlers when the Alienware Command Center (AWCC) interface is not initialized. A patch has been implemented to address this issue. Technical Details The core issue is that devices without the AWCC interface do not properly initialize the `awcc` variable within the `alienware-wmi-wmax` driver. Consequently, the sleep handlers attempt to dereference a NULL pointer, leading to a kernel crash or…

Overview CVE-2025-40233 identifies a vulnerability in the Linux kernel’s OCFS2 (Oracle Cluster File System version 2) file system. Specifically, the extent map cache could become stale after extents are moved or defragmented. This stale data can lead to subsequent operations operating on outdated extent flags, triggering a kernel panic (BUG_ON) due to inconsistencies between cached and on-disk data. Technical Details The vulnerability arises from a scenario involving reflinked extents, file range copies, and extent movement. The specific sequence of events leading to the issue is as follows: copy_file_range() creates a reflinked extent with the OCFS2_EXT_REFCOUNTED flag set. An ioctl(FITRIM) operation…