Security readout for executives and security teams
Plain-English summary
CVE-2021-33537 affects specific Weidmüller industrial WLAN devices. A low-privileged authenticated user can trigger a buffer overflow in web configuration parsing and potentially run code on the device. For operational networks, this is serious because compromise of wireless infrastructure can affect confidentiality, integrity, and availability.
Executive priority
Prioritize remediation for affected devices in production, OT, or remote-access paths. This is not confirmed as exploited, but the impact is high and the required privilege level is low enough to matter in shared operational environments.
Technical view
The vulnerability is in iw_webs configuration parsing. A specially crafted user name entry can overflow an error message buffer, leading to remote code execution. CVSS 3.1 is 8.8 with network attack vector, low complexity, low privileges required, no user interaction, and high impact across CIA.
Likely exposure
Exposure is limited to listed Weidmüller IE-WL(T)-BL-AP-CL-XX and IE-WL(T)-VL-AP-CL-XX industrial WLAN devices. Risk is highest where their web management plane is reachable by broad internal users, vendors, or less-trusted network segments.
Exploitation context
The bundle does not report active exploitation, and KEV is false. Exploitation requires authentication as a low-privilege user, but no user interaction. The public description confirms the vulnerability class and impact, but does not provide exploit prevalence or field telemetry.
Researcher notes
Evidence supports authenticated network RCE via CWE-120 buffer overflow in iw_webs username handling. The source bundle does not include fixed version details, exploit code, or confirmed exploitation. Treat firmware applicability and remediation specifics as vendor-advisory dependent.
Mitigation direction
- Check VDE-2021-026 and Weidmüller guidance for affected firmware and supported fixes.
- Apply vendor-approved firmware updates or mitigations when confirmed by the advisory.
- Restrict WLAN device management interfaces to trusted administration networks only.
- Remove unnecessary low-privilege accounts and enforce least privilege.
- Monitor authentication and configuration-change logs for unusual low-privilege activity.
Validation and detection
- Inventory Weidmüller WLAN devices by product family and order number.
- Compare deployed firmware and model details against VDE-2021-026.
- Confirm management interfaces are not reachable from untrusted segments.
- Review local user accounts and remove stale or unnecessary access.
- Check logs for suspicious configuration parsing, login, or account activity.
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-120: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-33537 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/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:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.