CVE-2023-31085Public exploit

System crash via zero-erasesize UBI attachment

Published Apr 24, 2023 · Updated Aug 2, 2024

Divide-by-zero in the Linux kernel 6.2 UBI driver allows local users to crash the system by attaching a zero-erasesize MTD device. During UBI device attachment, ctrl_cdev_ioctl reaches mtd_div_by_eb, which passes mtd->erasesize to do_div without rejecting a zero value. Triggering the ioctl requires CAP_SYS_RESOURCE in the initial user namespace; the demonstrated consequence is a kernel crash, not data access or code execution.

CVSS severity5.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in the Linux kernel 6.2 UBI driver allows local users to crash the system by attaching a zero-erasesize MTD device. During UBI device attachment, ctrl_cdev_ioctl reaches mtd_div_by_eb, which passes mtd->erasesize to do_div without rejecting a zero value. Triggering the ioctl requires CAP_SYS_RESOURCE in the initial user namespace; the demonstrated consequence is a kernel crash, not data access or code execution.

The record

CVE
CVE-2023-31085
Published
Apr 24, 2023
Updated
Aug 2, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-369, T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-369Divide By Zero
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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