Siemens SIMATIC S7-1500 Use After Free (CVE-2021-36086)

low Tenable OT Security Plugin ID 504029

Synopsis

The remote OT asset is affected by a vulnerability.

Description

The CIL compiler in SELinux 3.2 has a use-after-free in cil_reset_classpermission (called from cil_reset_classperms_set and cil_reset_classperms_list).

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Refer to the vendor advisory.

Plugin Details

Severity: Low

ID: 504029

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 11/13/2025

Updated: 11/13/2025

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 2.2

CVSS v3

Risk Factor: Low

Base Score: 3.3

Temporal Score: 3

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5, cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 12/12/2023

Vulnerability Publication Date: 12/12/2023

Reference Information

CVE: CVE-2021-36086

CWE: 416

Detections

Analytics