BusyBox FAT volume parser divide-by-zero DoS
CVE-2026-124742 Published on November 11, 2026
Busybox: divide-by-zero in the volume_id fat prober via a zero sectors_per_cluster value
A flaw was found in BusyBox. The volume identification component fails to properly validate cluster parameters when analyzing specially formatted FAT filesystems. An attacker able to present a crafted storage device or disk image can trigger a divide-by-zero condition when partition scanning utilities inspect the volume. This issue causes the probing utilities to crash unexpectedly, resulting in a Denial of Service (DoS) that can disrupt device discovery and system boot operations.
Vulnerability Analysis
CVE-2026-124742 is exploitable with local system access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public. 17 days later.
Weakness Type
Divide By Zero
The product divides a value by zero. This weakness typically occurs when an unexpected value is provided to the product, or if an error occurs that is not properly detected. It frequently occurs in calculations involving physical dimensions such as size, length, width, and height.
Products Associated with CVE-2026-124742
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