CVE-2025-70100

What it is

A divide-by-zero vulnerability in the ext4_block_set_lb_size function in src/ext4_blockdev.c of the lwext4 1.0.0 library allows attackers to cause a denial of service by providing a malformed ext4 filesystem image that results in a zero logical block size. The vulnerability is triggered during mount or image processing and leads to a Floating-Point Exception (FPE) under sanitizers or a runtime crash in standard builds due to missing validation of lb_size.

At a glance

Exploitability

Can be exploited locally on the machine without logging in, but needs a user to act. High risk of service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-06-03 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-22 19:10 UTC Last updatedMost recent change to the record

Details

Published

2026-06-03 14:16 UTC

Last modified

2026-07-22 19:10 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-369

Record status

Modified

Affected

• Gkostka lwext4 1.0.0

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High