Kernel corruption via changing loop-device block size
Published Dec 27, 2024 · Updated Aug 5, 2026
Out-of-bounds write in Linux hfsplus allows local users to corrupt kernel memory while mounting an HFS+ image on a loop device. hfsplus_read_wrapper allocates a buffer using one logical block size, but hfsplus_submit_bio can reread a changed size and write beyond that allocation. Exploitation requires local access to mount the image and concurrently issue LOOP_SET_BLOCK_SIZE on a writable loop-device descriptor; successful corruption can panic the kernel or enable privilege escalation.
Summary
What happened
Out-of-bounds write in Linux hfsplus allows local users to corrupt kernel memory while mounting an HFS+ image on a loop device. hfsplus_read_wrapper allocates a buffer using one logical block size, but hfsplus_submit_bio can reread a changed size and write beyond that allocation. Exploitation requires local access to mount the image and concurrently issue LOOP_SET_BLOCK_SIZE on a writable loop-device descriptor; successful corruption can panic the kernel or enable privilege escalation.
The record
- CVE
- CVE-2024-56548
- Published
- Dec 27, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- 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?
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- Affected versionversion=3.0.8 <3.1
- Affected versionversion=3.1
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <06cbfbb13ac88f4154c2eb4bc4176f9d10139847
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <1c82587cb57687de3f18ab4b98a8850c789bedcf
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <21900e8478126ff6afe3b66679f676e74d1f8830
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <2667c9b7b76efcbc7adbfea249892f20c313b0da
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <3d7bda75e1a6239db053c73acde17ca146317824
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <baccb5e12577b7a9eff54ffba301fdaa0f3ee5a8
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <bfeecda050aa9376f642d5b2a71c4112cc6c8216
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <e8a2b1c1c2ea85e9a5a2d0c5a5a7e7c639feb866
- Affected versionversion=6596528e391ad978a6a120142cba97a1d7324cb6 <f57725bcc5816425e25218fdf5fb6923bc578cdf
- Affected versionversion=c53c89aba3ebdfc3e9acdb18bb5ee9d2f8a328d0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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