CVE-2025-21867

Kernel memory corruption via undersized XDP test packet

Published Mar 27, 2025 · Updated Sep 8, 2026

Use-after-free in the Linux kernel BPF test-run path allows local users to corrupt kernel memory through undersized XDP test data. bpf_test_init accepts user_data shorter than an Ethernet header, after which eth_skb_pkt_type reads skb data as though that header existed. Reachability requires local access to BPF_PROG_TEST_RUN with live XDP frames; triggering the defect can expose or alter kernel memory or crash the system.

CVSS severity7.8
High
EPSS probability0.19%
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 kernel BPF test-run path allows local users to corrupt kernel memory through undersized XDP test data. bpf_test_init accepts user_data shorter than an Ethernet header, after which eth_skb_pkt_type reads skb data as though that header existed. Reachability requires local access to BPF_PROG_TEST_RUN with live XDP frames; triggering the defect can expose or alter kernel memory or crash the system.

The record

CVE
CVE-2025-21867
Published
Mar 27, 2025
Updated
Sep 8, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 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

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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=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=V3.1.6 <*
The Linux Kernel Organization · Linuxversion=5.18; version=be3d72a2896cb24090f268dce4aa8a304d40bc23 <1a9e1284e87d59b1303b69d1808d310821d6e5f7; version=be3d72a2896cb24090f268dce4aa8a304d40bc23 <6b3d638ca897e099fa99bd6d02189d3176f80a47; version=be3d72a2896cb24090f268dce4aa8a304d40bc23 <972bafed67ca73ad9a56448384281eb5fd5c0ba3; version=be3d72a2896cb24090f268dce4aa8a304d40bc23 <d56d8a23d95100b65f40438639dd82db2af81c11; version=be3d72a2896cb24090f268dce4aa8a304d40bc23 <f615fccfc689cb48977d275ac2e391297b52392b
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.6 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.6 <*

Published CVSS scores

7.8Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Linux kernel CNACVSS: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
T1068Exploitation for Privilege Escalation

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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