CVE-2026-89573 (CVSS 7.8)

Description

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.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/35cd3b278448c79614f65ab6bbc9ed348d847df9 https://git.kernel.org/stable/c/4538a287bdf5d0f9a379c678e5262b9f5783f547 https://git.kernel.org/stable/c/522fa26da24ccaa298ebe3c1c97395d2d63dfc21 https://git.kernel.org/stable/c/7bf4b5cb42a4e27f36bcbc6209d82a5da9c0168c https://git.kernel.org/stable/c/a530a9a419a7c5fdb7dae55ffa2dd7a130631842 https://git.kernel.org/stable/c/a8237cb8fa0a628d903e76635bfdeae4202036b9 https://git.kernel.org/stable/c/ac4a5eb8b002a0742c938fc98b922e243f53573a https://git.kernel.org/stable/c/cb409b38b0232ee4385ef55cddcd6fbdd011a8a2

Frequently Asked Questions

What is CVE-2026-89573? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-89573? +

CVE-2026-89573 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-89573? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-89573