CVE-2020-25669Public exploit

Local kernel compromise via stale reinit work

Published May 26, 2021 · Updated Aug 4, 2024

Use-after-free in the Sun keyboard driver in Linux Kernel 5.9.4 allows local users to crash the kernel or execute arbitrary code. sunkbd_interrupt can queue sunkbd_reinit before teardown frees its sunkbd structure, leaving the worker to dereference an alias after the pointer is cleared. Reachability requires CONFIG_KEYBOARD_SUNKBD=y and local access capable of driving the affected line-discipline sequence.

CVSS severity7.8
High
EPSS probability0.63%
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 Sun keyboard driver in Linux Kernel 5.9.4 allows local users to crash the kernel or execute arbitrary code. sunkbd_interrupt can queue sunkbd_reinit before teardown frees its sunkbd structure, leaving the worker to dereference an alias after the pointer is cleared. Reachability requires CONFIG_KEYBOARD_SUNKBD=y and local access capable of driving the affected line-discipline sequence.

The record

CVE
CVE-2020-25669
Published
May 26, 2021
Updated
Aug 4, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

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  1. Affected versionversion=5.9.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.9.4

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
4.1Amazon LinuxCVSS:3.1/AV:P/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
7.8NIST NVDCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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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