CVE-2025-38715 in Linux
Summary
by MITRE • 09/04/2025
In the Linux kernel, the following vulnerability has been resolved:
hfs: fix slab-out-of-bounds in hfs_bnode_read()
This patch introduces is_bnode_offset_valid() method that checks the requested offset value. Also, it introduces check_and_correct_requested_length() method that checks and correct the requested length (if it is necessary). These methods are used in hfs_bnode_read(), hfs_bnode_write(), hfs_bnode_clear(), hfs_bnode_copy(), and hfs_bnode_move() with the goal to prevent the access out of allocated memory and triggering the crash.
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Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2025-38715 represents a critical heap-based buffer overflow in the Linux kernel's HFS (Hierarchical File System) implementation. This issue manifests within the hfs_bnode_read() function where improper bounds checking allows for out-of-bounds memory access. The flaw occurs when processing file system operations on HFS formatted volumes, potentially enabling malicious actors to exploit memory corruption through crafted file system structures. The vulnerability directly impacts the kernel's memory management subsystem and could lead to system instability or privilege escalation depending on the execution context.
The technical implementation of this vulnerability stems from inadequate validation of memory access parameters within the HFS file system driver. Specifically, the hfs_bnode_read() function processes node-based file system structures without sufficient bounds checking on the requested offset values. This allows attackers to specify memory locations beyond the allocated buffer boundaries, creating potential for memory corruption that could trigger kernel crashes or more severe exploitation scenarios. The vulnerability operates at the kernel level where memory management is critical for system stability and security.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation and denial of service conditions. When exploited, the out-of-bounds memory access can corrupt kernel data structures, leading to unpredictable behavior including system panics, data corruption, or in more sophisticated attack scenarios, arbitrary code execution within kernel space. The affected functions hfs_bnode_read(), hfs_bnode_write(), hfs_bnode_clear(), hfs_bnode_copy(), and hfs_bnode_move() all share this vulnerability, amplifying the potential attack surface. This vulnerability particularly affects systems running Linux kernels with HFS file system support, including various desktop and server configurations that utilize HFS or HFS+ formatted storage devices.
The patch addressing CVE-2025-38715 introduces comprehensive validation mechanisms through two new helper functions: is_bnode_offset_valid() and check_and_correct_requested_length(). These methods establish proper bounds checking for memory access operations across all affected HFS node manipulation functions. The implementation follows established security principles by applying the principle of least privilege and defensive programming techniques to prevent unauthorized memory access patterns. This approach aligns with common security frameworks and represents a standard mitigation strategy for buffer overflow vulnerabilities in kernel space operations. The fix ensures that all memory access operations within the HFS subsystem validate requested offsets and lengths before proceeding with memory operations, thereby preventing the slab-out-of-bounds conditions that could lead to system compromise. The solution demonstrates adherence to security best practices and follows the CWE-129 principle of input validation for buffer overflow prevention.