System interruption via unchecked JFS slot index
Published Dec 27, 2024 · Updated Aug 5, 2026
An out-of-bounds read in Linux JFS allows context-dependent attackers to interrupt the system through a malformed directory tree. jfs_readdir in fs/jfs/jfs_dtree.c uses each signed stbl entry directly as an index into a 128-slot directory page without first validating that it is between 0 and 127. Reachability requires a mounted JFS filesystem containing the malformed tree and a directory read; the demonstrated result is an out-of-bounds kernel access.
Summary
What happened
An out-of-bounds read in Linux JFS allows context-dependent attackers to interrupt the system through a malformed directory tree. jfs_readdir in fs/jfs/jfs_dtree.c uses each signed stbl entry directly as an index into a 128-slot directory page without first validating that it is between 0 and 127. Reachability requires a mounted JFS filesystem containing the malformed tree and a directory read; the demonstrated result is an out-of-bounds kernel access.
The record
- CVE
- CVE-2024-56596
- Published
- Dec 27, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-129, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 27, 2024CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <839f102efb168f02dfdd46717b7c6dddb26b015e
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ff7579554571d92e3deab168f5a7d7b146ed368
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <97e693593162eef6851d232f0c8148169ed46a5c
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9efe72eefd4c4a7ce63b3e4d667d766d2b360cb4
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b62f41aeec9d250144c53875b507c1d45ae8c8fc
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e7d376f94f72b020f84e77278b150ec1cc27502c
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ff9fc48fab0e1ea0d423c23c99b91bba178f0b05
- 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 JFS directory reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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