Security readout for executives and security teams
Plain-English summary
CVE-2021-34569 is a critical memory corruption issue in WAGO I/O-Check Service. A remote unauthenticated attacker could crash the diagnostic tool and affect confidentiality, integrity, and availability. The provided sources do not confirm active exploitation or a named patch.
Executive priority
Prioritize within industrial and operational technology risk management because the flaw is critical, remotely reachable, and unauthenticated. Immediate focus should be exposure reduction and vendor confirmation, especially for systems supporting production, safety, or facility operations.
Technical view
The issue is described as CWE-787 out-of-bounds write in WAGO I/O-Check Service across multiple WAGO product families. CVSS 3.1 is 9.8: network reachable, low complexity, no privileges, no user interaction, unchanged scope, and high impact to confidentiality, integrity, and availability.
Likely exposure
Exposure is most likely where listed WAGO 750-81xx, 750-82xx, 752-8303, or 762-series products run the affected I/O-Check Service and are reachable over a network. The bundle’s version/status detail is incomplete, so confirm exact affected firmware with WAGO or VDE.
Exploitation context
The source bundle supports remote unauthenticated attack potential from the CVSS vector and description. It does not identify public exploitation, proof-of-concept availability, or inclusion in CISA KEV. Treat internet or broad internal reachability as high risk until vendor guidance is confirmed.
Researcher notes
Evidence supports a critical out-of-bounds write in WAGO I/O-Check Service, but the provided bundle does not include detailed exploit mechanics, fixed versions, or mitigation text. The affected-version data appears sparse, so do not overstate product applicability without the vendor advisory.
Mitigation direction
- Review the VDE advisory and WAGO guidance for confirmed firmware or service-specific fixes.
- Inventory listed WAGO product families and identify where I/O-Check Service is enabled.
- Restrict diagnostic service access to trusted management networks only.
- Remove any direct internet exposure for affected WAGO services.
- Monitor for diagnostic tool crashes or unexpected service instability.
Validation and detection
- Confirm whether deployed models match the listed WAGO product families.
- Compare firmware and service status against the VDE advisory.
- Verify diagnostic interfaces are not reachable from untrusted networks.
- Review security monitoring for crashes, resets, or suspicious access attempts.
- Document uncertainty where vendor version applicability remains unclear.
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-787: 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-2021-34569 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
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.