Bug 2401521 (CVE-2023-53569)

Summary: CVE-2023-53569 kernel: ext2: Check block size validity during mount
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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An integer overflow vulnerability was found in the Linux kernel ext2 filesystem's block size validation during mount. A local user with privileges to mount filesystems can mount a crafted ext2 image with an excessively large log_block_size value in the superblock, causing the shift operation computing the actual block size to overflow and trigger undefined behavior, which results in denial of service through kernel crash or unpredictable system behavior.
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Description OSIDB Bzimport 2025-10-04 16:05:18 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ext2: Check block size validity during mount

Check that log of block size stored in the superblock has sensible
value. Otherwise the shift computing the block size can overflow leading
to undefined behavior.
Comment 1 Alexander B 2025-10-06 14:07:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100452-CVE-2023-53569-181e@gregkh/T