Kernel crash via JFS trim-remount race
Published Oct 21, 2024 · Updated May 12, 2026
Use-after-free in the Linux kernel's JFS subsystem allows local users to crash the kernel by racing filesystem trim against remount. The dbUnmount path frees bmap while jfs_ioc_trim can concurrently reach dbFreeBits, whose mutex operation reads the freed object because the paths lack s_umount synchronization. Local low-privileged access and a mounted JFS filesystem are required; successful exploitation can expose, corrupt, or interrupt kernel state.
Summary
What happened
Use-after-free in the Linux kernel's JFS subsystem allows local users to crash the kernel by racing filesystem trim against remount. The dbUnmount path frees bmap while jfs_ioc_trim can concurrently reach dbFreeBits, whose mutex operation reads the freed object because the paths lack s_umount synchronization. Local low-privileged access and a mounted JFS filesystem are required; successful exploitation can expose, corrupt, or interrupt kernel state.
The record
- CVE
- CVE-2024-49903
- Published
- Oct 21, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-416, T1529
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 21, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=0 <*
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What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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Your stack
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