CVE-2025-21676

Local system crash via unchecked page allocation

Published Jan 31, 2025 · Updated Sep 8, 2026

NULL pointer dereference in the Linux FEC Ethernet driver allows local users to crash affected systems during memory pressure. The fec_enet_update_cbd function continues after page_pool_dev_alloc_pages returns NULL and dereferences the missing page. Triggering requires low-privileged local access, an active FEC interface, and a page-allocation failure; the resulting kernel crash interrupts the system.

CVSS severity7.5
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux FEC Ethernet driver allows local users to crash affected systems during memory pressure. The fec_enet_update_cbd function continues after page_pool_dev_alloc_pages returns NULL and dereferences the missing page. Triggering requires low-privileged local access, an active FEC interface, and a page-allocation failure; the resulting kernel crash interrupts the system.

The record

CVE
CVE-2025-21676
Published
Jan 31, 2025
Updated
Sep 8, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 31, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 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=V3.1.5 <*
  2. Affected versionversion=V3.1.6 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*; version=V3.1.6 <*
The Linux Kernel Organization · Linuxversion=6.1; version=95698ff6177b5f1f13f251da60e7348413046ae4 <001ba0902046cb6c352494df610718c0763e77a5; version=95698ff6177b5f1f13f251da60e7348413046ae4 <1425cb829556398f594658512d49292f988a2ab0; version=95698ff6177b5f1f13f251da60e7348413046ae4 <8a0097db0544b658c159ac787319737712063a23; version=95698ff6177b5f1f13f251da60e7348413046ae4 <eacdcc14f3c8d4c1447565521e792ddb3a67e08d
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*; version=V3.1.6 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*; version=V3.1.6 <*

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.7SUSECVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5CISA ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7SUSECVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5Linux CNACVSS:3.1/AV:N/AC:L/PR:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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