CVE-2025-39921

Memory-device probe failure via zero-frequency division

Published Oct 1, 2025 · Updated May 11, 2026

Denial of service in the Linux kernel 6.14 through 6.16.5 allows local users to prevent attached memory-device probing. The mchp_coreqspi_supports_op callback divides by op->max_freq while that field is zero during probe, producing INT_MAX for baud_rate_val. Reachability requires the Microchip CoreQSPI driver and attached SPI memory; the bounded consequence is failure to probe that memory device.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel 6.14 through 6.16.5 allows local users to prevent attached memory-device probing. The mchp_coreqspi_supports_op callback divides by op->max_freq while that field is zero during probe, producing INT_MAX for baud_rate_val. Reachability requires the Microchip CoreQSPI driver and attached SPI memory; the bounded consequence is failure to probe that memory device.

The record

CVE
CVE-2025-39921
Published
Oct 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=13529647743d906ed3cf991f1d77727e7ff1fb6f <89e7353f522f5cf70cb48c01ce2dcdcb275b8022
  2. Affected versionversion=13529647743d906ed3cf991f1d77727e7ff1fb6f <ac8a13f35d5b8996582b3f97b924838a5c570c18
  3. Affected versionversion=6.14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=13529647743d906ed3cf991f1d77727e7ff1fb6f <89e7353f522f5cf70cb48c01ce2dcdcb275b8022; version=13529647743d906ed3cf991f1d77727e7ff1fb6f <ac8a13f35d5b8996582b3f97b924838a5c570c18; version=6.14

Published CVSS scores

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

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

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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