CVE-2025-38698 in Linux
Summary
by MITRE • 09/04/2025
In the Linux kernel, the following vulnerability has been resolved:
jfs: Regular file corruption check
The reproducer builds a corrupted file on disk with a negative i_size value. Add a check when opening this file to avoid subsequent operation failures.
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Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2025-38698 resides within the Linux kernel's JFS (Journaled File System) implementation, representing a critical file system corruption issue that can lead to severe operational disruptions. This flaw specifically manifests when a regular file is created with a negative i_size value, which violates fundamental file system assumptions about file size parameters. The JFS file system, designed for high performance and reliability in enterprise environments, fails to properly validate file metadata during the opening process, creating a pathway for subsequent operations to encounter critical failures. The vulnerability stems from insufficient input validation and parameter checking within the file system's inode handling mechanisms, where the system does not adequately verify that file size attributes remain within acceptable positive integer ranges.
The technical flaw occurs at the intersection of file system metadata management and kernel-level file operations, specifically when the JFS implementation processes files that have been deliberately or inadvertently corrupted with negative size values. When a file with a negative i_size attribute is encountered during the file opening sequence, the system fails to implement proper validation checks that would normally prevent such malformed data from proceeding through the operational pipeline. This design oversight allows corrupted file metadata to propagate through the system, potentially causing kernel panics, data corruption, or denial of service conditions when subsequent file operations attempt to process these invalid file descriptors. The vulnerability operates at the kernel level, meaning that successful exploitation can compromise the entire system's stability and integrity, as the file system layer directly interfaces with core kernel components.
The operational impact of CVE-2025-38698 extends beyond simple file corruption, potentially affecting system availability and data integrity across environments that utilize JFS file systems. When a corrupted file with negative size values is opened, the system may experience cascading failures during read, write, or metadata operations, leading to system crashes or the inability to access legitimate files within the same file system. This vulnerability particularly affects enterprise servers, storage systems, and embedded devices that rely on JFS for data management, as the corruption can propagate through file system operations and potentially compromise the stability of the entire operating environment. The impact is exacerbated by the fact that the vulnerability can be triggered through normal file operations, making it difficult to detect and prevent through traditional security monitoring approaches, and it directly violates the fundamental assumptions of file system integrity that underpin Linux kernel reliability standards.
Mitigation strategies for CVE-2025-38698 require immediate kernel updates and patches that implement proper validation checks for i_size attributes during file opening operations. The fix must include comprehensive input validation that prevents negative size values from being processed through the JFS file system's operational pipeline, effectively creating a defensive barrier against corrupted file metadata. Organizations should implement monitoring solutions that can detect unusual file system behavior patterns and establish automated scanning routines to identify potentially corrupted files before they can cause system failures. Additionally, system administrators should consider implementing file system integrity checks that regularly scan for malformed metadata and establish robust backup procedures to ensure data recovery capabilities in case of corruption events. This vulnerability aligns with CWE-129 and CWE-191 categories related to input validation and integer overflow issues, and represents a significant concern for ATT&CK technique T1486 related to data manipulation and system resource compromise. The fix should be prioritized in all production environments using JFS file systems, with particular attention to critical infrastructure and enterprise storage solutions that may be vulnerable to this class of file system corruption issues.