Security readout for executives and security teams
Plain-English summary
This issue can let an unauthenticated remote attacker make affected WAGO I/O-Check Service deployments unavailable. The reported impact is denial of service, not data theft or takeover. Business urgency is highest where listed WAGO controllers support production, building, or industrial operations and the service is reachable from untrusted networks.
Executive priority
Prioritize remediation for any exposed operational technology networks. This is not described as a confidentiality breach, but disruption of industrial or automation controllers can create business downtime and safety-adjacent operational risk.
Technical view
CVE-2021-34568 is a CWE-770 resource allocation flaw in WAGO I/O-Check Service. CVSS 3.1 is 7.5: network reachable, low complexity, no privileges, no user interaction, availability impact high. The source says a specially crafted packet containing OS commands can provoke denial of service.
Likely exposure
Likely exposure is WAGO environments using I/O-Check Service on the listed WAGO 750, 752, and 762 product families. The provided bundle does not clearly state exact vulnerable firmware boundaries beyond FW1 entries, so teams should verify affected status against WAGO/VDE guidance.
Exploitation context
The bundle does not report known active exploitation, and CISA KEV status is false. The risk is still operationally relevant because the attack is remote and unauthenticated if the vulnerable service is reachable.
Researcher notes
Do not assume code execution or compromise beyond availability impact from the supplied evidence. The phrase "containing OS commands" appears in the CVE description, but the stated consequence is denial of service only. Exact affected-release detail and remediation text require vendor advisory confirmation.
Mitigation direction
- Review WAGO/VDE advisory VDE-2020-036 for vendor fixes or mitigations.
- Apply vendor-recommended firmware or service updates where applicable.
- Restrict I/O-Check Service to trusted engineering networks only.
- Block access from internet, enterprise, and third-party network paths.
- Monitor affected controllers for availability degradation or unexpected service failures.
Validation and detection
- Inventory listed WAGO 750, 752, and 762 product families.
- Confirm whether I/O-Check Service is enabled on each asset.
- Check whether the service is reachable from untrusted network zones.
- Compare firmware and service versions with WAGO/VDE advisory guidance.
- Review logs and monitoring for unexplained denial-of-service symptoms.
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-770: 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-2021-34568 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:N/I:N/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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary 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:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://cert.vde.com/en/advisories/VDE-2020-036/CVE 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.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.