CVE Catalog

CVE-2026-89573

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel, the dm-array array_block_check() function only compares the header against itself, so a block with value_size 4 and max_entries 1018 passes validation. Pointing the dm-cache mappings root at a hint block causes element_at() to stride 8 bytes over 4-byte entries and reach beyond a 4096-byte block.

Risk Assessment

Crafted metadata can cause out-of-bounds reads in the kernel, leading to system crashes or potential data disclosure/corruption.

Recommendation

Update the Linux kernel to a version where get_ablock() and __shadow_ablock() reject blocks whose value size disagrees with the caller's expected value size.

Related vulnerabilities

Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: dm array: reject an array block whose value size is not the caller's array_block_check() can only compare the header against itself, so a block with value_size 4 and max_entries 1018 is internally consistent and passes. dm-cache keeps two arrays -- mappings at 8 bytes and hints at 4 -- and the roots for both live in the superblock. Point the mappings root at a hint block and __load_mappings() walks it through an info whose value size is 8, so element_at() strides 8 bytes over 4-byte entries and reaches offset 8160 of a 4096-byte block. get_ablock() and __shadow_ablock() are the two places that hold the block and the caller at once. Reject there when the two value sizes disagree. Arrays only ever read their own blocks, so this fires on crafted metadata only.

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