Medium

PROFINET DCP NULL Pointer Dereference in Siemens SCALANCE LPE9403

IdentifiersCVE-2025-40576CWE-476· NULL Pointer Dereference

CVE-2025-40576 is a NULL pointer dereference in the PROFINET Discovery and basic Configuration Protocol (DCP) daemon on Siemens SCALANCE LPE9403 devices. The daemon does not properly validate incoming PROFINET packets; a specially crafted packet can trigger a NULL pointer dereference and crash the dcpd process. The vulnerability affects SCALANCE LPE9403 firmware versions earlier than V4.0 HF0.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

An unauthenticated attacker on the adjacent Layer 2 network can cause a denial of service by crashing the PROFINET DCP daemon. This may disrupt device discovery and configuration operations, cause the device to appear unreachable to SCADA or monitoring systems, and potentially prevent IP-address assignment where DCP is used during commissioning.

Mitigation

If you can’t patch tonight, do this now.

Until firmware updates can be deployed, isolate SCALANCE LPE9403 devices from untrusted Layer 2 networks using OT network segmentation and restrict access to PROFINET-capable switch ports and VLANs. Limit physical and logical access to the affected network segment, monitor for malformed or anomalous PROFINET DCP traffic, and apply access controls that prevent untrusted systems from transmitting Layer 2 traffic to device interfaces.

Remediation

Patch, then assume compromise.

Upgrade affected Siemens SCALANCE LPE9403 devices to firmware V4.0 HF0 or a later Siemens-provided fixed version.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

SiemensScalance Lpe9403 Firmwareoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app

nozomi networks blogNews

Sep 15, 2026

Exploiting the Edge: Vulnerabilities in the Siemens SCALANCE LPE9403

NULL-pointer-dereference flaw (CWE-476) in Siemens SCALANCE LPE9403 firmware before V4.0 HF0, with availability impact reflected in its CVSS vector.

nozomi networks blogNews

Sep 10, 2026

Fuzzing Siemens PROFINET DCP: An Emulation-Driven Approach with Unicorn-AFL

A NULL-pointer-dereference vulnerability in the PROFINET DCP service (dcpd.bin) of Siemens SCALANCE LPE9403 firmware through V4.0 HF0. Crafted Layer-2 DCP traffic from an adjacent, unauthenticated attacker can crash the daemon and cause denial of service.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2025-40576

NVD

nvd.nist.gov/vuln/detail/CVE-2025-40576

MITRE CWE · CWE-476

NULL Pointer Dereference

Vendor Advisory

cert-portal.siemens.com/productcert/html/ssa-327438.html

PROFINET DCP NULL Pointer Dereference in Siemens SCALANCE LPE9403

IdentifiersCVE-2025-40576CWE-476· NULL Pointer Dereference