Security readout for executives and security teams
Plain-English summary
This Siemens SIMATIC issue is a stored cross-site scripting flaw in the device web interface. A highly privileged authenticated user could plant malicious script through a PLC/station name. When another authorized user opens the communication parameters page, that script runs in their session. It is rated critical, but exploitation requires specific privileges and user interaction.
Executive priority
Treat as priority remediation for environments where these Siemens controllers are reachable by engineering workstations or shared users. The business risk is session compromise inside industrial management interfaces, but exploitation is not unauthenticated and no active exploitation is cited.
Technical view
CVE-2026-25786 is CWE-79 in Siemens SIMATIC controller web interfaces. The PLC/station name shown on the communication parameters page is not properly validated or sanitized. An authenticated attacker authorized to download a TIA project can inject script that executes when a user with appropriate rights views that page.
Likely exposure
Exposure is limited to listed Siemens SIMATIC Drive Controller and ET 200SP CPU/Open Controller products using the affected web interface. The source bundle does not provide reliable version ranges; affected entries show version "0" and duplicates. Confirm exact exposure against Siemens SSA-688146.
Exploitation context
No active exploitation is indicated by KEV or the provided sources. Practical exploitation requires network access, valid authentication, authorization to download a TIA project, and a victim user opening the affected communication page.
Researcher notes
CVSS 4.0 score is 9.3 with AV:N, AC:L, PR:H, UI:P and high vulnerable/subsequent system impacts. Version data in the bundle is incomplete and duplicated, so the Siemens advisory should be treated as authoritative for exact product status and fixes.
Mitigation direction
- Check Siemens SSA-688146 for affected versions, fixed firmware, and official workarounds.
- Restrict TIA project download privileges to trusted engineering users only.
- Limit device web interface access to trusted management networks.
- Review PLC/station names for unexpected script-like content.
- Monitor relevant web interface access after project downloads.
Validation and detection
- Inventory Siemens SIMATIC models named in the advisory.
- Map installed firmware and hardware variants to Siemens SSA-688146.
- Identify accounts allowed to download TIA projects into devices.
- Confirm whether the communication parameters page is reachable from non-management networks.
- Review recent station-name changes and related web access logs.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-25786 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.3 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H——siemensCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H2.36siemensVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/html/ssa-688146.htmlCVE reference, siemens
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.