CVE-2026-72369

Received Received - Intake

Integer Overflow in Minix Filesystem Block Count Calculation

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: minix: avoid overflow in bitmap block count calculation minix_check_superblock() uses minix_blocks_needed() to verify that the on-disk imap and zmap block counts are large enough for the advertised inode and zone counts. The helper currently performs DIV_ROUND_UP() in unsigned int arithmetic. A Minix v3 image can set s_ninodes or s_zones near UINT_MAX so the addition inside DIV_ROUND_UP() wraps to zero. That makes a zero imap/zmap block count look valid, after which minix_fill_super() can dereference s_imap[0] or s_zmap[0] even though no bitmap buffers were allocated. Impact: mounting a crafted Minix v3 image whose s_ninodes or s_zones is near UINT_MAX makes minix_check_superblock() accept a zero bitmap-block count and minix_fill_super() dereference s_imap[0]/s_zmap[0], panicking the kernel. The divisor is the bitmap capacity in bits, blocksize * 8, which is always a power of two: minix_fill_super() obtains the block size through sb_set_blocksize(), and blk_validate_block_size() rejects any size that is not a power of two. Use DIV_ROUND_UP_POW2(), which divides before adding the round-up term and so cannot overflow for a power-of-two divisor.

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-72369

EUVD

EUVD-2026-59268

Affected Vendors & Products

Vendor	Product	Version / Range
minix	minix	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a flaw in the Minix file system implementation. When mounting a crafted Minix v3 image with s_ninodes or s_zones set near UINT_MAX, the bitmap block count calculation overflows. This causes minix_check_superblock() to accept a zero bitmap-block count as valid, leading minix_fill_super() to dereference invalid memory locations and trigger a kernel panic.

Detection Guidance

This vulnerability is specific to the Linux kernel's Minix filesystem handling. Detection requires checking if your system runs a vulnerable kernel version. Inspect the kernel version with 'uname -a' and compare it against patched versions. No direct network detection commands are applicable as this is a local filesystem issue.

Impact Analysis

Exploiting this vulnerability could allow an attacker to crash the system by mounting a specially crafted Minix v3 image. This results in a denial-of-service condition, potentially disrupting services or causing system instability. It does not appear to allow arbitrary code execution or data theft.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a local denial-of-service issue in the Linux kernel's Minix filesystem driver, causing kernel panics when mounting crafted images. Compliance impacts would only occur if such crashes disrupt systems handling regulated data.

Mitigation Strategies

Update your Linux kernel to a patched version that includes the fix for this Minix filesystem vulnerability. Avoid mounting untrusted Minix v3 filesystem images until the system is updated. Monitor vendor advisories for kernel updates addressing this issue.

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