CVE-2025-21954

Service interruption via unreadable netmem transmission

Published Apr 1, 2025 · Updated Aug 5, 2026

Denial of service in Linux kernel 6.12 allows local users to interrupt the system by redirecting unreadable netmem packets. The forwarding path in net/core/dev.c passes RX socket buffers whose data cannot be read by the CPU into device transmission, where drivers invoke DMA-mapping APIs on addresses that must not be remapped. Reachability requires netmem/devmem RX plus a forwarding or traffic-control redirect path into device transmission, and the published impact is limited to availability.

CVSS severity5.5
Medium
EPSS probability0.48%
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 Linux kernel 6.12 allows local users to interrupt the system by redirecting unreadable netmem packets. The forwarding path in net/core/dev.c passes RX socket buffers whose data cannot be read by the CPU into device transmission, where drivers invoke DMA-mapping APIs on addresses that must not be remapped. Reachability requires netmem/devmem RX plus a forwarding or traffic-control redirect path into device transmission, and the published impact is limited to availability.

The record

CVE
CVE-2025-21954
Published
Apr 1, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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=6.12
  2. Affected versionversion=65249feb6b3df9e17bab5911ee56fa7b0971e231 <1c17c8ced25c5fbe424c7ad7ea11d33014a986b1
  3. Affected versionversion=65249feb6b3df9e17bab5911ee56fa7b0971e231 <454825019d2f0c59e5174ece9e713f45ad80beff
  4. Affected versionversion=65249feb6b3df9e17bab5911ee56fa7b0971e231 <f3600c867c99a2cc8038680ecf211089c50e7971

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=65249feb6b3df9e17bab5911ee56fa7b0971e231 <1c17c8ced25c5fbe424c7ad7ea11d33014a986b1; version=65249feb6b3df9e17bab5911ee56fa7b0971e231 <454825019d2f0c59e5174ece9e713f45ad80beff; version=65249feb6b3df9e17bab5911ee56fa7b0971e231 <f3600c867c99a2cc8038680ecf211089c50e7971

Published CVSS scores

5.5UbuntuCVSS: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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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