Siemens (CVE-2021-41991)

high Tenable.ot Plugin ID 500650


The remote OT asset is affected by a vulnerability.


The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement of cache entries. The code attempts to select a less-often-used cache entry by means of a random number generator, but this is not done correctly. Remote code execution might be a slight possibility.

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Refer to the vendor advisory.

See Also

Plugin Details

Severity: High

ID: 500650

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 4/28/2022

Updated: 4/28/2022

Risk Information


Risk Factor: Medium

Score: 4.4


Risk Factor: Medium

Base Score: 5

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2021-41991


Risk Factor: High

Base Score: 7.5

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

Vulnerability Information

CPE: cpe:/o:siemens:siplus_et_200sp_cp_1542sp-1_irc_tx_rail_firmware:-, cpe:/o:siemens:siplus_et_200sp_cp_1543sp-1_isec_firmware:-, cpe:/o:siemens:siplus_et_200sp_cp_1543sp-1_isec_tx_rail_firmware:-, cpe:/o:siemens:siplus_s7-1200_cp_1243-1_firmware:-, cpe:/o:siemens:siplus_s7-1200_cp_1243-1_rail_firmware:-

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 10/18/2021

Vulnerability Publication Date: 10/18/2021

Reference Information

CVE: CVE-2021-41991