CVE-2026-4438

Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) — kwetsbaarheid CVE-2026-4438

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

CVSS 5.4No patch available

This record: live connection— last retrieved: 24 September 2026 at 05:12.

Vendor

Siemens

Product

SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)

up to version vers:intdot/>=3.1.5|<3.1.6

Published

20 March 2026

Last modified

14 July 2026

Original source information

Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.

Technical description

CVSS 3.1 — vector details

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack vector

NETWORK

Privileges required

NONE

User interaction

NONE

Confidentiality

Limited

Integrity

Limited

Availability

None

EPSS — Exploit Prediction Scoring System

Probability of exploitation within 30 days

0.3%

Percentile

25e

Source: FIRST.org, updated on 23 September 2026.

Patch information

Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.

IACS Radar assessment

Our own interpretation and context for the source data above.

IACS Radar assessment

Our own interpretation and context for this vulnerability — not an official source.

IACS Radar priority score

38/ 100

Based on CVSS 5.4, EPSS 0.3%, industrial relevance 55/100.

Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.

Conditions for exploitation

•Network access to the affected device or segment is required.
•No valid credentials are needed.
•No user interaction required.

Operational impact & energy relevance

Limited impact on availability; the risk lies mainly with confidentiality or integrity of process data.

Assessed as relevant to the energy sector based on: Vermeld in een officiële CISA ICS Advisory, wat directe relevantie voor industriële besturingssystemen bevestigt. Vendor "Siemens" is a known supplier of equipment for the energy sector.

Recommended defensive measures

•Apply the latest firmware or software update and validate its integrity.
•Restrict network access to the affected device to a dedicated OT management segment.
•Implement network segmentation in line with zones and conduits (IEC 62443-3-2).
•Monitor for abnormal protocol traffic using an OT-aware detection system.

Industrial relevance score

55/ 100

• Mentioned in an official CISA ICS advisory, which confirms direct relevance to industrial control systems.
• Vendor "Siemens" is a known supplier of equipment for the energy sector.

Classification is provisional; manual verification by an OT security analyst is recommended.

Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 24 September 2026.

IEC 62443 mapping

IEC 62443-4-1FR3 · Systeemintegriteit

Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.

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