Kernel crash via unchecked JFS inode mode
Published Dec 8, 2025 · Updated May 11, 2026
Improper inode validation in Linux JFS allows local users to crash the kernel by opening an inode from a corrupted filesystem. In jfs_iget, every mode other than a regular file, directory, or symbolic link was passed to init_special_inode without confirming a valid special-file type. Exploitation requires access to a mounted malformed JFS filesystem; opening the invalid inode reaches the may_open kernel BUG and interrupts the host.
Summary
What happened
Improper inode validation in Linux JFS allows local users to crash the kernel by opening an inode from a corrupted filesystem. In jfs_iget, every mode other than a regular file, directory, or symbolic link was passed to init_special_inode without confirming a valid special-file type. Exploitation requires access to a mounted malformed JFS filesystem; opening the invalid inode reaches the may_open kernel BUG and interrupts the host.
The record
- CVE
- CVE-2025-40312
- Published
- Dec 8, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 8, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1795277a4e98d82e6451544d43695540cee042ea
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <19cce65709a8a2966203653028d9004e28e85bd5
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2870a7dec49ccdc3f6ae35da8f5d6737f21133a8
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <46c76cfa17d1828c1a889cb54cb11d5ef3dfbc0f
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7a5aa54fba2bd591b22b9b624e6baa9037276986
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8d6a9cbd276b3b85da0e7e98208f89416fed9265
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ce054a366c54992185c9514e489a14f145b10c29
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fabc1348bb8fe6bc80850014ee94bd89945f7f4d
- Affected versionversion=2.6.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- syzkaller malformed-filesystem reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo