CVE-2025-38222 Siemens CVE debrief

Who should care

Siemens SIMATIC S7-1500 operators, OT/ICS asset owners, Linux subsystem administrators on affected devices, and vulnerability/patch management teams responsible for industrial control environments.

Technical summary

The CVE description says ext4_prepare_inline_data used an unsigned int length, so pos + len could truncate during ext4_generic_write_inline_data. That can let write_begin succeed with an incorrect small length, and write_end later reaches BUG_ON(pos + len > EXT4_I(inode)->i_inline_size) in ext4_write_inline_data, causing a kernel BUG/Oops. The described fix is to use loff_t for the len parameter. In the supplied advisory corpus, Siemens ties the issue to the SIMATIC S7-1500 CPU family and its additional GNU/Linux subsystem, but the corpus does not provide a fixed version.

Defensive priority

Medium, with elevated operational priority in OT environments because the advisory lists no fix and the impact is a kernel crash/availability loss.

Recommended defensive actions

• Restrict interactive shell access on the additional GNU/Linux subsystem to trusted personnel only.
• Only build and run applications from trusted sources.
• Track Siemens ProductCERT and CISA advisories for a future fixed release and deploy it when available.
• Apply CISA/Siemens defense-in-depth guidance for the affected SIMATIC S7-1500 environment.
• Review whether local users or automation can reach the embedded Linux write path, and limit that access where possible.

Evidence notes

Source item ICSA-25-162-05 (published 2025-06-10, last updated 2026-05-14) contains the CVE description, affected Siemens SIMATIC S7-1500 product names, and mitigation text stating no fix is currently available. The CVE record links to the Linux ext4 inline_data overflow description and a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. The advisory corpus also includes Siemens CSAF/HTML references and CISA advisory links.

Official resources