Security readout for executives and security teams
Plain-English summary
This Siemens vulnerability can let an unauthenticated attacker on the same network disrupt affected controllers by abusing DHCP handling. The reported impact is mainly availability: a device can be assigned an invalid IP address, potentially interrupting building automation or embedded device operations.
Executive priority
Treat this as a high-priority OT availability issue where affected devices support building operations. Prioritize sites with DHCP enabled, shared networks, or limited segmentation. It is less urgent for isolated devices or products already above the Siemens fixed-version thresholds.
Technical view
CVE-2019-13939 is an input validation flaw in DHCP client handling across listed Siemens APOGEE, Desigo, TALON, Capital Embedded, Nucleus, and SIMOTICS products. Specially crafted DHCP packets can change a device IP address to an invalid value when DHCP client functionality is enabled. CVSS is 7.1, adjacent network, low complexity, no privileges, no user interaction.
Likely exposure
Exposure is most likely in operational technology or building automation networks using affected Siemens controllers or embedded components with DHCP client enabled. The attacker needs adjacent network access, so flat facilities networks, shared VLANs, or weakly controlled maintenance networks increase risk.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. The attack is not described as internet-routable; the CVSS vector requires adjacent network access. Evidence supports disruption potential, not confidentiality impact.
Researcher notes
Key validation points are product family, exact version, DHCP client state, and network adjacency. The source bundle names many affected ranges but does not provide exploit details. Avoid assuming internet exposure or active exploitation without additional evidence.
Mitigation direction
- Upgrade affected products to Siemens-listed non-affected versions where available.
- For products listed as all versions affected, follow Siemens advisory guidance.
- Disable DHCP client functionality where operationally safe and supported.
- Restrict access to building automation and OT network segments.
- Monitor for unexpected IP address changes on affected devices.
Validation and detection
- Inventory Siemens APOGEE, Desigo, TALON, Capital Embedded, Nucleus, and SIMOTICS assets.
- Compare firmware or software versions against the affected ranges.
- Confirm whether DHCP client functionality is enabled on each device.
- Review network segmentation for adjacent access to affected devices.
- Check logs or asset monitoring for unexpected IP changes.
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
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ATT&CK lookup starting points
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CWE-20: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-13939 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A: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.
CVSS vector scores
1 official scoreWe 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:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H2.84.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-434032.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-162506.pdfCVE reference · x_refsource_CONFIRM
- https://us-cert.cisa.gov/ics/advisories/icsa-20-105-06CVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/html/ssa-434032.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-162506.htmlCVE reference
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 Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.