Filesystem disclosure and corruption via reflink metadata overwrite
Published Oct 21, 2024 · Updated Aug 5, 2026
Improper input validation in Linux OCFS2 allows local users to read or corrupt filesystem data through a crafted reflink ioctl. ocfs2_reflink_xattr_inline reduces the destination inode's extent-record count to reserve inline xattr space after the reflink tree is attached, overwriting live extent records when more than 227 already exist. An unprivileged user needs a locally mounted OCFS2 filesystem, a crafted source file, and write access to a destination directory; exploitation can expose or overwrite disk blocks, remount the filesystem read-only, or panic clustered nodes.
Summary
What happened
Improper input validation in Linux OCFS2 allows local users to read or corrupt filesystem data through a crafted reflink ioctl. ocfs2_reflink_xattr_inline reduces the destination inode's extent-record count to reserve inline xattr space after the reflink tree is attached, overwriting live extent records when more than 227 already exist. An unprivileged user needs a locally mounted OCFS2 filesystem, a crafted source file, and write access to a destination directory; exploitation can expose or overwrite disk blocks, remount the filesystem read-only, or panic clustered nodes.
The record
- CVE
- CVE-2024-49958
- Published
- Oct 21, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-20, T1485
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 21, 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=1926bf8ae44d80c9f50103f11fc4f17e2e2bf684
- Affected versionversion=1e7e4c9ae2a78a6791a2ca91a6a400f94855f01e
- Affected versionversion=26a849f49fb3347d126a0ed6611173f903374ef4
- Affected versionversion=3.0.87 <3.1
- Affected versionversion=3.10.2 <3.11
- Affected versionversion=3.11
- Affected versionversion=3.2.49 <3.3
- Affected versionversion=3.4.54 <3.5
- Affected versionversion=3.9.11 <3.10
- Affected versionversion=3a32958d2ac96070c53d04bd8e013c97b260b5e6
- Affected versionversion=93f26306db89c9dc37885b76a1082e6d54d23b16
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <020f5c53c17f66c0a8f2d37dad27ace301b8d8a1
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <5c2072f02c0d75802ec28ec703b7d43a0dd008b5
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <5c9807c523b4fca81d3e8e864dabc8c806402121
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <5ca60b86f57a4d9648f68418a725b3a7de2816b0
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <637c00e06564a945e9d0edb3d78d362d64935f9f
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <74364cb578dcc0b6c9109519d19cbe5a56afac9a
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <96ce4c3537114d1698be635f5e36c62dc49df7a4
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <9f9a8f3ac65b4147f1a7b6c05fad5192c0e3c3d9
- Affected versionversion=ef962df057aaafd714f5c22ba3de1be459571fdf <aac31d654a0a31cb0d2fa36ae694f4e164a52707
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
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Public exploit references
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Technologies
Your stack
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Your stack
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