CVE-2021-33536
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn Weidmueller Industrial WLAN devices in multiple versions an exploitable denial-of-service vulnerability exists in ServiceAgent functionality. A specially crafted packet can cause an integer underflow, triggering a large memcpy that will access unmapped or out-of-bounds memory. An attacker can send this packet while unauthenticated to trigger this vulnerability.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceWeidmueller Industrial WLAN devices contain a denial-of-service vulnerability in the ServiceAgent component. An unauthenticated remote attacker can send a specially crafted packet that triggers an integer underflow, causing an excessively large memcpy() operation that accesses unmapped or out-of-bounds memory, resulting in device failure.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10<= 1.16.18<= 1.11.10CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Weidmueller device modelCheck the device label, web interface, or SNMP inventory to confirm the exact model (e.g., IE WL BL AP CL EU, IE WLT BL AP CL EU, etc.) from the list of affected productsAffected if The device model matches one of the eight affected product names listed in the CVE
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Determine the installed firmware versionAccess the device web interface under System > Firmware or use the Weidmueller configuration tool to retrieve the current firmware versionAffected if The firmware version is <= 1.16.18 or <= 1.11.10
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Verify ServiceAgent network exposureCheck network configuration to determine if the ServiceAgent service (typically port 8080/tcp or vendor-specified port) is accessible from untrusted network segmentsAffected if ServiceAgent is exposed to network segments that contain untrusted or external hosts
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Confirm ServiceAgent is enabledLog into the device administrative interface and verify that the ServiceAgent component is enabled in the service configurationAffected if ServiceAgent is running and enabled on the device
The device is affected if it is a Weidmueller Industrial WLAN model from the affected product list, runs firmware version <= 1.16.18 or <= 1.11.10, and has the ServiceAgent component enabled and accessible on the network.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor-provided security patches or firmware updates for Weidmueller Industrial WLAN devices. If no patch is available, isolate affected devices behind network segmentation and restrict access to the ServiceAgent service from untrusted networks.
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,544.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33536 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-33536 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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