CVE-2021-44879

Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) — vulnerability CVE-2021-44879

In gc_data_segment in fs/f2fs/gc.c in the Linux kernel before 5.16.3, special files are not considered, leading to a move_data_page NULL pointer dereference.

CVSS 5.5Patch available

This record: live connection— last retrieved: 7 November 2026 at 00:32.

Vendor

Siemens

Products

SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0), SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

up to version vers:intdot/>=3.1.0|<3.1.5

Published

14 February 2022

Last modified

14 October 2026

Original source information

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

Technical description

In gc_data_segment in fs/f2fs/gc.c in the Linux kernel before 5.16.3, special files are not considered, leading to a move_data_page NULL pointer dereference.

CVSS 3.1 — vector details

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

Attack vector

LOCAL

Privileges required

NONE

User interaction

REQUIRED

Confidentiality

None

Integrity

None

Availability

High

EPSS — Exploit Prediction Scoring System

Probability of exploitation within 30 days

1.5%

Percentile

74e

Source: FIRST.org, updated on 6 November 2026.

Patch information

Update to V3.1.5 or later version

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

39/ 100

Based on CVSS 5.5, EPSS 1.5%, 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

•Local or adjacent access to the device is required.
•No valid credentials are needed.
•User interaction (for example opening a file) is required.

Operational impact & energy relevance

Possible loss of visibility of or control over the process upon successful exploitation.

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 7 November 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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