Medium [CVE-2026-89557] Linux kernel md driver: Denial of service via integer overflow in bad block handling
This medium-severity Red Hat Linux advisory covers CVE-2026-89557.
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Summary
A flaw was found in the Linux kernel's Multiple Device (md) driver. A local attacker with control over a malicious disk image could provide a specially crafted on-disk superblock with an invalid 'bblog_shift' value.
This invalid value can lead to an integer overflow when processing bad block information, potentially causing a system crash or data corruption, resulting in a denial of service. Red Hat severity: Moderate — CVSS 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-190.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
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