CVE-2025-21877

Kernel warning via unchecked GL620A USB endpoints

Published Mar 27, 2025 · Updated May 11, 2026

Improper endpoint validation in the Linux kernel allows local users to trigger a kernel warning with a crafted GL620A USB device. genelink_bind() uses endpoint assumptions without confirming that the device exposes the required bulk endpoints, so usbnet can submit an URB with a mismatched pipe type. Exploitation requires local access capable of presenting artificial USB descriptors, and the demonstrated consequence is an availability-affecting kernel warning during network transmission.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper endpoint validation in the Linux kernel allows local users to trigger a kernel warning with a crafted GL620A USB device. genelink_bind() uses endpoint assumptions without confirming that the device exposes the required bulk endpoints, so usbnet can submit an URB with a mismatched pipe type. Exploitation requires local access capable of presenting artificial USB descriptors, and the demonstrated consequence is an availability-affecting kernel warning during network transmission.

The record

CVE
CVE-2025-21877
Published
Mar 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=2.6.14
  2. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <1cf9631d836b289bd5490776551961c883ae8a4f
  3. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <24dd971104057c8828d420a48e0a5af6e6f30d3e
  4. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <4e8b8d43373bf837be159366f0192502f97ec7a5
  5. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <5f2dbabbce04b1ffcd6d8d07564adb94db577536
  6. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <67ebc3391c8377738e97a43374054d9718fdb6e4
  7. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <9bcb8cbc3e5d67eb223bfb7e2291a270dbb699dc
  8. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <a2ee5e55b50a97d13617c8653482c0ad4decff8c
  9. Affected versionversion=47ee3051c856cc2aa95d35d577a8cb37279d540f <ded25730c96949cb8b048b29c557e38569124943

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.14; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <1cf9631d836b289bd5490776551961c883ae8a4f; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <24dd971104057c8828d420a48e0a5af6e6f30d3e; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <4e8b8d43373bf837be159366f0192502f97ec7a5; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <5f2dbabbce04b1ffcd6d8d07564adb94db577536; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <67ebc3391c8377738e97a43374054d9718fdb6e4; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <9bcb8cbc3e5d67eb223bfb7e2291a270dbb699dc; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <a2ee5e55b50a97d13617c8653482c0ad4decff8c; version=47ee3051c856cc2aa95d35d577a8cb37279d540f <ded25730c96949cb8b048b29c557e38569124943

Published CVSS scores

5.5Amazon LinuxCVSS: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
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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