CVE Catalog

CVE-2023-52497

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.28%

20th percentile - higher than 20% of all known CVEs

Summary

In the Linux kernel, the EROFS filesystem has a vulnerability in LZ4 in-place decompression that can lead to data corruption. The issue arises from uncertain buffer ordering when mapping two separate virtual buffers, exposed on new Intel x86 processors with FSRM feature.

Risk Assessment

Data corruption in the EROFS filesystem may lead to loss of data integrity or system crash.

Recommendation

Apply a Linux kernel update containing the fix that strictly uses the decompression buffer for LZ4 in-place decompression.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: erofs: fix lz4 inplace decompression Currently EROFS can map another compressed buffer for inplace decompression, that was used to handle the cases that some pages of compressed data are actually not in-place I/O. However, like most simple LZ77 algorithms, LZ4 expects the compressed data is arranged at the end of the decompressed buffer and it explicitly uses memmove() to handle overlapping: __________________________________________________________ |_ direction of decompression --> ____ |_ compressed data _| Although EROFS arranges compressed data like this, it typically maps two individual virtual buffers so the relative order is uncertain. Previously, it was hardly observed since LZ4 only uses memmove() for short overlapped literals and x86/arm64 memmove implementations seem to completely cover it up and they don't have this issue. Juhyung reported that EROFS data corruption can be found on a new Intel x86 processor. After some analysis, it seems that recent x86 processors with the new FSRM feature expose this issue with "rep movsb". Let's strictly use the decompressed buffer for lz4 inplace decompression for now. Later, as an useful improvement, we could try to tie up these two buffers together in the correct order.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS