CVE-2025-38591Public exploit

Service interruption via narrow BPF context read

Published Aug 19, 2025 · Updated Sep 8, 2026

Improper input validation in the Linux kernel BPF verifier allows local users to interrupt service with a narrow context-pointer read. bpf_skb_is_valid_access accepts a one-byte access inside the __sk_buff sk pointer field; bpf_convert_ctx_access then aligns the offset, leaves target_size at zero, and reaches a verifier warning. A low-privileged user able to load the crafted BPF program can trigger the warning and availability loss; Siemens firmware V3.1.6 and later embeds the affected subsystem.

CVSS severity5.5
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in the Linux kernel BPF verifier allows local users to interrupt service with a narrow context-pointer read. bpf_skb_is_valid_access accepts a one-byte access inside the __sk_buff sk pointer field; bpf_convert_ctx_access then aligns the offset, leaves target_size at zero, and reaches a verifier warning. A low-privileged user able to load the crafted BPF program can trigger the warning and availability loss; Siemens firmware V3.1.6 and later embeds the affected subsystem.

The record

CVE
CVE-2025-38591
Published
Aug 19, 2025
Updated
Sep 8, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-20, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 19, 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=4.13; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <058a0da4f6d916a79b693384111bb80a90d73763; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <202900ceeef67458c964c2af6e1427c8e533ea7c; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <33660d44e789edb4f303210c813fc56d56377a90; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <7847c4140e06f6e87229faae22cc38525334c156; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <e09299225d5ba3916c91ef70565f7d2187e4cca0; version=f96da09473b52c09125cc9bf7d7d4576ae8229e0 <feae34c992eb7191862fb1594c704fbbf650fef8
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

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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

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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-20Improper Input Validation
T1499Endpoint Denial of Service

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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