Security readout for executives and security teams
Plain-English summary
Certain Siemens SIMATIC ET 200 interface modules and PN couplers can be forced into an unresponsive state by a valid S7 disconnect request over TCP port 102. The impact is operational downtime: affected devices may require a physical power cycle to recover.
Executive priority
Treat as a high-priority operational resilience issue for sites using affected Siemens distributed I/O or coupler devices. Prioritize environments where production depends on these devices and where TCP/102 is reachable beyond tightly controlled automation networks.
Technical view
The issue is improper handling of S7 protocol Disconnect Request COTP DR TPDUs on TCP/102, causing an improper session state and denial of service. CVSS v4.0 is 8.7 with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely in industrial networks using the listed Siemens SIMATIC ET 200 or SIPLUS interface modules and PN/MF or PN/PN couplers where TCP/102 is reachable.
Exploitation context
The provided bundle does not show CISA KEV listing or confirmed active exploitation. The vulnerability is remotely reachable on a common Siemens S7 communications port, but the sources only support denial of service, not code execution or data compromise.
Researcher notes
Evidence supports CWE-400 resource management failure leading to availability loss. The bundle names many exact Siemens order numbers and version ranges, but does not provide exploit proof, KEV status, or universal fixed versions for every affected product.
Mitigation direction
- Apply Siemens firmware updates or workarounds listed in SSA-674753 where available.
- For products listed as all versions affected, follow current Siemens guidance before compensating controls.
- Restrict TCP/102 access to required engineering and controller hosts only.
- Segment affected industrial devices from enterprise, internet-facing, and remote-access networks.
- Plan maintenance windows because recovery may require power cycling affected devices.
Validation and detection
- Inventory exact Siemens product names, order numbers, and firmware versions.
- Compare each asset against the affected-version ranges in CVE-2025-40944 and SSA-674753.
- Confirm whether TCP/102 is reachable from non-control-network segments.
- Review operations logs for unexplained device unresponsiveness requiring power cycling.
- Verify remediation status against Siemens advisory guidance after maintenance.
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-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2025-40944 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
- High
- CVSS
- 8.7 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N——siemensCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6siemensVulnerability scoring details
Base CVSS 4.0 score
8.7HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-674753.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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.