CVE-2021-20109Network attack vector

Remote heap corruption via oversized POST response

Published Jul 19, 2021 · Updated Aug 3, 2024

Heap overflow in ManageEngine AssetExplorer Agent 1.0.34 allows remote attackers to corrupt heap memory via an oversized POST response. AEAgent.cpp converts the response to Unicode with vswprintf and writes it into a fixed 0x2000-byte buffer without enforcing the payload length. Exploitation requires network access, impersonation of the configured AssetExplorer server IP, a NEWSCAN request to port 9000, and control of the agent callback response.

CVSS severity7.8
High
EPSS probability1.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in ManageEngine AssetExplorer Agent 1.0.34 allows remote attackers to corrupt heap memory via an oversized POST response. AEAgent.cpp converts the response to Unicode with vswprintf and writes it into a fixed 0x2000-byte buffer without enforcing the payload length. Exploitation requires network access, impersonation of the configured AssetExplorer server IP, a NEWSCAN request to port 9000, and control of the agent callback response.

The record

CVE
CVE-2021-20109
Published
Jul 19, 2021
Updated
Aug 3, 2024
Vendor
ManageEngine
Product
AssetExplorer
Classifications
CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.34

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ManageEngine · AssetExplorerversion=1.0.34

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.8TenableAV:N/AC:L/Au:N/C:N/I:C/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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