CVE-2025-21915

Kernel-address disclosure via unlocked CDX sysfs read

Published Apr 1, 2025 · Updated Aug 5, 2026

Use-after-free in the Linux CDX bus driver allows local users to disclose a kernel address through a race in a sysfs attribute. driver_override_show() reads cdx_dev->driver_override without the device lock while driver_override_store() can replace and free the same string. Reachability requires local access and overlap between the sysfs read and a concurrent override update; the documented consequence is kernel-address disclosure.

CVSS severity7.8
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux CDX bus driver allows local users to disclose a kernel address through a race in a sysfs attribute. driver_override_show() reads cdx_dev->driver_override without the device lock while driver_override_store() can replace and free the same string. Reachability requires local access and overlap between the sysfs read and a concurrent override update; the documented consequence is kernel-address disclosure.

The record

CVE
CVE-2025-21915
Published
Apr 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2959ab247061e67485d83b6af8feb3761ec08cb9 <0439d541aa8d3444ad41c39e39eb71acb57acde3
  2. Affected versionversion=2959ab247061e67485d83b6af8feb3761ec08cb9 <8473135f89c0949436a22adb05b8cece2fb3da91
  3. Affected versionversion=2959ab247061e67485d83b6af8feb3761ec08cb9 <91d44c1afc61a2fec37a9c7a3485368309391e0b
  4. Affected versionversion=2959ab247061e67485d83b6af8feb3761ec08cb9 <d7b339bbc887bcfc1a5b620bfc70c6fbb8f733bf
  5. Affected versionversion=6.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2959ab247061e67485d83b6af8feb3761ec08cb9 <0439d541aa8d3444ad41c39e39eb71acb57acde3; version=2959ab247061e67485d83b6af8feb3761ec08cb9 <8473135f89c0949436a22adb05b8cece2fb3da91; version=2959ab247061e67485d83b6af8feb3761ec08cb9 <91d44c1afc61a2fec37a9c7a3485368309391e0b; version=2959ab247061e67485d83b6af8feb3761ec08cb9 <d7b339bbc887bcfc1a5b620bfc70c6fbb8f733bf; version=6.4

Published CVSS scores

7.8OSVCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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