System hang via EA inode allocation under lock
Published Jul 12, 2024 · Updated May 11, 2026
Improper locking in the ext4 extended-attribute path allows local users to hang Linux through a crafted corrupted filesystem. The ext4_xattr_set_entry() path allocates a new extended-attribute inode while holding the external xattr block's buffer lock, nesting allocation locks beneath it. Exploitation requires local low-privileged access and a corrupted ext4 filesystem whose quota file uses an xattr block as a data block, causing a deadlock and system hang.
Summary
What happened
Improper locking in the ext4 extended-attribute path allows local users to hang Linux through a crafted corrupted filesystem. The ext4_xattr_set_entry() path allocates a new extended-attribute inode while holding the external xattr block's buffer lock, nesting allocation locks beneath it. Exploitation requires local low-privileged access and a corrupted ext4 filesystem whose quota file uses an xattr block as a data block, causing a deadlock and system hang.
The record
- CVE
- CVE-2024-40972
- Published
- Jul 12, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-667, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 12, 2024CVE 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
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.13
- Affected versionversion=e50e5129f384ae282adebfb561189cdb19b81cee <0752e7fb549d90c33b4d4186f11cfd25a556d1dd
- Affected versionversion=e50e5129f384ae282adebfb561189cdb19b81cee <0a46ef234756dca04623b7591e8ebb3440622f0b
- Affected versionversion=e50e5129f384ae282adebfb561189cdb19b81cee <111103907234bffd0a34fba070ad9367de058752
- Affected versionversion=e50e5129f384ae282adebfb561189cdb19b81cee <737fb7853acd5bc8984f6f42e4bfba3334be8ae1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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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