Security readout for executives and security teams
Plain-English summary
Siemens embedded products may mishandle UDP packets because the payload length declared in the IP header is not checked. In affected deployments, this can expose data or disrupt UDP-based application behavior. Business urgency depends on network reachability and the UDP applications running on the device.
Executive priority
Treat as high priority for Siemens embedded systems with UDP network exposure. The issue is remotely reachable and unauthenticated, but urgency should be based on actual deployment, segmentation, and whether affected UDP applications support sensitive or operational functions.
Technical view
CVE-2021-31345 is CWE-1284 in Siemens Capital Embedded AR Classic and PLUSCONTROL 1st Gen. The unchecked UDP payload length can cause information leak and denial-of-service side effects depending on user-defined UDP applications. CVSS 3.1 is 7.5: network exploitable, low complexity, no privileges, no user interaction.
Likely exposure
Exposure is most likely where affected Siemens embedded runtime products process UDP traffic from reachable networks. Listed scope includes Capital Embedded AR Classic 431-422 all versions, Capital Embedded AR Classic R20-11 before V2303, and PLUSCONTROL 1st Gen all versions.
Exploitation context
The source bundle does not indicate known active exploitation, and KEV status is false. The CVSS vector shows remote network attackability without authentication, but the actual impact depends on deployed UDP application behavior. No exploit details are needed to assess exposure.
Researcher notes
The public description gives root cause and impact classes but not detailed trigger conditions. CVSS emphasizes confidentiality impact, while the description also mentions possible denial of service depending on application behavior. Avoid assuming exploitability beyond affected UDP-processing contexts.
Mitigation direction
- Inventory affected Siemens products and versions in operational environments.
- Prioritize Capital Embedded AR Classic R20-11 versions below V2303 for vendor update review.
- Restrict UDP exposure to trusted network segments where operationally possible.
- Check Siemens ProductCERT advisories for product-specific updates and mitigations.
- Monitor UDP-facing services for crashes, resets, or unusual data exposure.
Validation and detection
- Confirm whether listed Siemens products are present in asset inventory.
- Map which affected systems can receive UDP traffic from untrusted networks.
- Identify user-defined applications running on top of UDP on affected systems.
- Verify installed versions against Siemens affected-version statements.
- Review Siemens ProductCERT advisories before approving remediation exceptions.
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-1284: 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-2021-31345 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
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A: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.
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-114589.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-044112.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-620288.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-845392.pdfCVE reference · x_refsource_MISC
- https://cert-portal.siemens.com/productcert/html/ssa-114589.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-044112.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-620288.htmlCVE reference
- https://cert-portal.siemens.com/productcert/html/ssa-845392.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 Validation of Specified Quantity in Input
Improper Validation of Specified Quantity in Input represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.