CVE-2021-40358: 
Siemens SIMATIC WinCC vulnerability analysis and mitigation

A path traversal vulnerability (CVE-2021-40358) was identified in multiple versions of Siemens SIMATIC PCS 7 and SIMATIC WinCC systems. The vulnerability affects the web server component where legitimate file operations do not properly neutralize special elements within pathnames (NVD, Siemens Advisory).

The vulnerability is classified as an Improper Limitation of a Pathname to a Restricted Directory (CWE-22). It received a CVSS v3.1 base score of 9.8 CRITICAL (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) from NVD and 9.9 CRITICAL (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) from Siemens AG (NVD).

If exploited, an attacker could cause the pathname to resolve to a location outside of the restricted directory on the server, enabling them to read, write, or delete unexpected critical files (CISA).

Siemens has released updates for affected products and recommends updating to the latest versions. For systems where updates are not available, Siemens recommends hardening the application's host to prevent local access by untrusted personnel and disabling the webserver or only enabling it temporarily when needed (CISA).