Security readout for executives and security teams
Plain-English summary
Certain Weidmuller industrial WLAN devices can be tricked into treating selected remote traffic as local traffic, bypassing web authentication. The issue depends on device hostname processing and requires authenticated SNMP access to trigger. A successful attack could expose or change device management functions, affecting confidentiality, integrity, and availability.
Executive priority
Prioritize this where affected WLAN devices support industrial operations or bridge sensitive network segments. The issue is high impact, but known evidence indicates privileged access is required and active exploitation is not confirmed.
Technical view
CVE-2021-33539 is a CWE-287 authentication bypass in hostname processing on specified Weidmuller IE-WL and IE-WLT industrial WLAN AP/client devices. The CVSS 3.1 score is 7.2 with network access, low complexity, high privileges, no user interaction, and high C/I/A impact.
Likely exposure
Exposure is limited to environments running the listed Weidmuller industrial WLAN models, especially where SNMP and web management are reachable beyond tightly controlled administration networks.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not marked CISA KEV. Exploitation requires authenticated SNMP access, but could bypass web authentication once triggered.
Researcher notes
The public bundle identifies affected model families and product numbers but does not include patch details, exploit observations, or full advisory text. Avoid assuming broader Weidmuller impact without matching product numbers or vendor confirmation.
Mitigation direction
- Inventory Weidmuller IE-WL and IE-WLT industrial WLAN devices against the affected model list.
- Check the CERT@VDE advisory and Weidmuller guidance for supported firmware or workarounds.
- Restrict SNMP and web management access to trusted administration networks only.
- Review SNMP accounts and remove unnecessary management access.
- Monitor affected devices for unexpected hostname changes or management activity.
Validation and detection
- Confirm whether listed product numbers are deployed in operational networks.
- Verify SNMP is not reachable from untrusted networks.
- Review device hostname configuration for unexpected or unauthorized values.
- Check management logs for unusual SNMP or web administration activity.
- Document firmware versions and compare them with vendor guidance.
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-287: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-33539 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
- 7.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/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:H/UI:N/S:U/C:H/I:H/A:H1.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.2HighVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://cert.vde.com/en-us/advisories/vde-2021-026CVE reference · x_refsource_CONFIRM
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 Authentication
Improper Authentication represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.