PatchSiren cyber security CVE debrief

CVE-2026-27661 Siemens CVE debrief

CVE-2026-27661 is a medium-severity information disclosure vulnerability affecting Siemens SINEC Security Monitor. The vulnerability was disclosed on October 8, 2024, and subsequently assigned CVE identifier on March 10, 2026, with the advisory updated on March 12, 2026. The affected application leaks confidential information in metadata and files, including contributor information and email addresses, on the SSM Server component. This vulnerability has a CVSS 3.1 score of 4.3 (MEDIUM) with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N, indicating network-accessible attack vector with low attack complexity, requiring low privileges, with no user interaction needed, and resulting in low confidentiality impact. Siemens has released a vendor fix in version 4.9.0 or later to address this issue.

Vendor: Siemens
Product: SINEC Security Monitor
CVSS: MEDIUM 4.3
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-10-08
Original CVE updated: 2026-03-12
Advisory published: 2024-10-08
Advisory updated: 2026-03-12

Who should care

Organizations operating Siemens SINEC Security Monitor in industrial control system environments should prioritize this update. Security teams responsible for OT/ICS infrastructure, network administrators managing SSM Server deployments, and compliance officers concerned with information disclosure risks should assess exposure. Organizations with regulatory requirements for protecting contributor and contact information in industrial monitoring systems should apply the vendor fix promptly.

Technical summary

The vulnerability exists in the SSM Server component of Siemens SINEC Security Monitor, where confidential information is leaked through metadata and files. Specifically, the application exposes contributor information and email addresses that should remain protected. The attack vector is network-based with low complexity, requiring only low privileges and no user interaction. The confidentiality impact is rated as low, with no integrity or availability impact. The vulnerability is classified under CWE-1230 (Exposure of Sensitive Information Through Metadata).

Defensive priority

medium

Recommended defensive actions

Update Siemens SINEC Security Monitor to version 4.9.0 or later to remediate the information disclosure vulnerability.
Review and restrict network access to SSM Server components to authorized personnel only.
Audit existing SSM Server deployments for exposure of sensitive metadata and contributor information.
Apply defense-in-depth strategies for industrial control systems as recommended by CISA.
Monitor for unauthorized access attempts to SSM Server metadata endpoints.

Evidence notes

The vulnerability description is sourced from CISA CSAF advisory ICSA-24-284-06, which references Siemens ProductCERT advisory SSA-430425. The CVSS vector and remediation details are explicitly documented in the CSAF source. The affected product is confirmed as SINEC Security Monitor with CSAFPID-0001 identifier.

Official resources

CVE-2026-27661 was initially disclosed on October 8, 2024, as part of CISA advisory ICSA-24-284-06. The CVE identifier was added to the advisory on March 10, 2026, with subsequent republication on March 12, 2026, based on Siemens ProductCOR