CVE-2021-20109
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 · uneditedDue to the Asset Explorer agent not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address. This will allow an attacker to send a NEWSCAN request to a listening agent on the network as well as receive the agent's HTTP request verifying its authtoken. In AEAgent.cpp, the agent responding back over HTTP is vulnerable to a Heap Overflow if the POST payload response is too large. The POST payload response is converted to Unicode using vswprintf. This is written to a buffer only 0x2000 bytes big. If POST payload is larger, then heap overflow will occur.
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 · high confidenceThe Asset Explorer agent fails to validate HTTPS certificates, enabling an attacker on the network to spoof the server IP and send malicious NEWSCAN requests to the agent. Additionally, in AEAgent.cpp, when processing POST payload responses, the data is converted to Unicode via vswprintf and written to a fixed 0x2000 (8192 byte) buffer. If the POST payload exceeds this size, a heap overflow occurs.
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= 1.0.34CVSS 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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 AssetExplorer agent versionLocate the installed version of ManageEngine AssetExplorer in the system (check program files, about section, or version info)Affected if Installed version equals 1.0.34 exactly (the only version listed as affected)
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Verify HTTPS certificate validation configurationInspect the AssetExplorer agent configuration files or settings for SSL/TLS certificate validation settingsAffected if Certificate validation is disabled or set to bypass trust verification
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Confirm network exposure of the agentDetermine if the AssetExplorer agent listens on network ports and could receive requests from untrusted network locationsAffected if Agent is reachable from network segments without proper access controls
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Assess POST payload handlingReview agent logs or network captures to determine if the agent processes POST requests with payloadsAffected if Agent processes POST responses from servers without validating payload size against the 8192-byte buffer limit
The environment is affected if AssetExplorer version is 1.0.34, the agent does not validate HTTPS certificates, and the agent can receive POST responses with payloads exceeding 8192 bytes.
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 dataEnable proper HTTPS certificate validation in the Asset Explorer agent to prevent man-in-the-middle attacks. Implement bounds checking on POST payload size before the vswprintf conversion and either allocate dynamic buffers or truncate oversized payloads to prevent heap overflow.
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20109 — 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-2021-20109 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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- Version or environment caveats, and links to real fixes
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